Simvastatin radiosensitizes differentiated and stem-like breast cancer cell lines and is associated with improved local control in inflammatory breast cancer patients treated with postmastectomy radiation

Reported rates of local failure after adjuvant radiation for women with inflammatory breast cancer (IBC) and triple-negative non-IBC are higher than those of women with receptor-expressing non-IBC. These high rates of locoregional recurrence are potentially influenced by the contribution of radioresistant cancer stem cells to these cancers. Statins have been shown to target stem cells and improve disease-free survival among IBC patients. We examined simvastatin radiosensitization of multiple subtypes of breast cancer cell lines in vitro in monolayer and mammosphere-based clonogenic assays and examined the therapeutic benefit of statin use on local control after postmastectomy radiation (PMRT) among IBC patients. We found that simvastatin radiosensitizes mammosphere-initiating cells (MICs) of IBC cell lines (MDA-IBC3, SUM149, SUM190) and of the metaplastic, non-IBC triple-negative receptor cell line (SUM159). However, simvastatin radioprotects MICs of non-IBC cell lines MCF-7 and SKBR3. In a retrospective clinical study of 519 IBC patients treated with PMRT, 53 patients used a statin. On univariate analysis, actuarial 3-year local recurrence-free survival (LRFS) was higher among statin users, and on multivariate analysis, triple negative breast cancer, absence of lymphatic invasion, neoadjuvant pathological tumor response to preoperative chemotherapy, and statin use were independently associated with higher LRFS. In conclusion, patients with IBC and triple-negative non-IBC breast cancer have the highest rates of local failure, and there are no available known radiosensitizers. We report significant improvement in local control after PMRT among statin users with IBC and significant radiosensitization across triple-negative and IBC cell lines of multiple subtypes using simvastatin. These data suggest that simvastatin should be justified as a radiosensitizing agent by a prospective clinical trial.

Aldehyde dehydrogenase1 immunohistochemical staining in primary breast cancer cells independently predicted overall survival but did not correlate with the presence of circulating or disseminated tumors cells

PURPOSE

We hypothesized that aldehyde dehydrogenase 1 (ALDH1) staining in breast cancer tumor cells might be a simple surrogate for the presence of circulating tumor cells (CTCs) or disseminated tumor cells (DTCs).

EXPERIMENTAL DESIGN

Whole tissue primary tumor sections from 121 patients enrolled in a clinical trial assessing CTCs and DTCs at the time of surgery were stained for ALDH1 and scored by a dedicated breast pathologist blinded to outcome. Clinical data was extracted and staining was correlated to clinical variables and outcome by Fisher's exact test, the Log rank test and Cox proportional hazards regression analysis respectively. P < 0.05 was considered significant.

RESULTS

ALDH1 staining in tumor cells was present in 12% of cases (15/121). In univariate analysis, ALDH1 tumor staining predicted worse overall survival (71% vs. 91% at 5 years P = 0.0074) and was an independent predictor on multivariable analysis of worse overall survival, (HR 4.93) after adjusting for stage, ER, grade, LVI, age and neoadjuvant chemotherapy (P = 0.04). ALDH1 was significantly associated with estrogen receptor (ER) negative (P value = 0.029) primary tumors but not the presence of CTCs or DTCs by multivariate logistic regression. Positive ALDH staining in non-tumor cells of any pattern or morphology was common but did not correlate with CTCs or DTCs, other clinical variables, or outcome.

CONCLUSION

ALDH1 tumor staining was associated with ER -negative breast cancer and was an independent predictor of OS. However, it did not correlate to putative cancer stem cell surrogates CTCs and/or DTCs.

Statistical modeling approach to quantitative analysis of interobserver variability in breast contouring

PURPOSE

To develop a new approach for interobserver variability analysis.

METHODS AND MATERIALS

Eight radiation oncologists specializing in breast cancer radiation therapy delineated a patient's left breast "from scratch" and from a template that was generated using deformable image registration. Three of the radiation oncologists had previously received training in Radiation Therapy Oncology Group consensus contouring for breast cancer atlas. The simultaneous truth and performance level estimation algorithm was applied to the 8 contours delineated "from scratch" to produce a group consensus contour. Individual Jaccard scores were fitted to a beta distribution model. We also applied this analysis to 2 or more patients, which were contoured by 9 breast radiation oncologists from 8 institutions.

RESULTS

The beta distribution model had a mean of 86.2%, standard deviation (SD) of ±5.9%, a skewness of -0.7, and excess kurtosis of 0.55, exemplifying broad interobserver variability. The 3 RTOG-trained physicians had higher agreement scores than average, indicating that their contours were close to the group consensus contour. One physician had high sensitivity but lower specificity than the others, which implies that this physician tended to contour a structure larger than those of the others. Two other physicians had low sensitivity but specificity similar to the others, which implies that they tended to contour a structure smaller than the others. With this information, they could adjust their contouring practice to be more consistent with others if desired. When contouring from the template, the beta distribution model had a mean of 92.3%, SD ± 3.4%, skewness of -0.79, and excess kurtosis of 0.83, which indicated a much better consistency among individual contours. Similar results were obtained for the analysis of 2 additional patients.

CONCLUSIONS

The proposed statistical approach was able to measure interobserver variability quantitatively and to identify individuals who tended to contour differently from the others. The information could be useful as feedback to improve contouring consistency.

Shortened radiation therapy schedules for early-stage breast cancer: a review of hypofractionated whole-breast irradiation and accelerated partial breast irradiation

Breast-conserving therapy consisting of segmental mastectomy followed by whole-breast irradiation (WBI) has become widely accepted as an alternative to mastectomy as a treatment for women with early-stage breast cancer. WBI is typically delivered over the course of 5-6 weeks to the whole breast. Hypofractionated whole-breast irradiation and accelerated partial breast irradiation have developed as alternative radiation techniques for select patients with favorable early-stage breast cancer. These radiation regimens allow for greater patient convenience and the potential for decreased health care costs. We review here the scientific rationale behind delivering a shorter course of radiation therapy using these distinct treatment regimens in this setting as well as an overview of the published data and pending trials comparing these alternative treatment regimens to WBI.

Therapeutic radiation dose delivered to the low axilla during whole breast radiation therapy in the prone position: implications for targeting the undissected axilla

PURPOSE

One interpretation of the American College of Surgeons Oncology Group Z0011 trial is that whole breast radiation therapy, known to treat a portion of the low axilla when delivered in the supine position, can treat residual microscopic disease in patients with involved axillary nodes that were not removed by axillary dissection. The purpose of this study was to quantify radiation dose delivered to the axilla for patients treated in the prone position.

METHODS AND MATERIALS

We analyzed treatment plans from 40 consecutive patients who received radiation targeting the intact breast with tangent fields in the prone position. Axillary levels were contoured using Radiation Therapy Oncology Group (RTOG) definitions and radiation dose- volume calculations were made for axillary levels, heart, and lungs. We generated revised plans for 10 patients by modifying the tangent beams to increase axillary dose and compared original with modified plans.

RESULTS

The median proportion of the axilla covered by 90% of the prescription dose was 13% of level I (range, 0%-61%), 0% of level II (range, 0%-6%), and 0% of level III (range, 0%-0%). More of the level I axilla was covered in obese compared with nonobese patients (P = .013). Level I coverage did not differ significantly by laterality (P = .740) or tumor location (P = .527). Modification of the treatment plans significantly increased level I coverage (P = .005) with all modified plans delivering 90% of the prescription dose to at least 96% of the level I axilla. The modified plans had increased lung (P = .005) and heart (P = .028) dose, which were within acceptable RTOG normal tissue constraints.

CONCLUSIONS

Most patients treated with standard whole breast tangential radiation in the prone position receive subtherapeutic dose to the level I and II axilla. Patients treated in the prone position who require therapeutic radiation dose to the low axilla need treatment field modification; this is feasible for many patients using tangent fields.

Primary tumor resection as a component of multimodality treatment may improve local control and survival in patients with stage IV inflammatory breast cancer

BACKGROUND

To the authors' knowledge, the benefit of primary tumor resection among patients with metastatic inflammatory breast cancer (IBC) is unknown.

METHODS

The authors reviewed 172 cases of metastatic IBC. All patients received chemotherapy with or without radiotherapy and/or surgery. Patients were classified as responders or nonresponders to chemotherapy. The 5-year overall survival (OS) and distant progression-free survival (DPFS) and local control at the time of last follow-up were evaluated.

RESULTS

A total of 79 patients (46%) underwent surgery. OS and DPFS were better among patients treated with surgery versus no surgery (47% vs 10%, respectively [P<.0001] and 30% vs 3%, respectively [P<.0001]). Surgery plus radiotherapy was associated with better survival compared with treatment with surgery or radiotherapy alone (OS rate: 50% vs 25% vs 14%, respectively; DPFS rate: 32% vs 18% vs 15%, respectively [P<.0001 for both]). Surgery was associated with better survival for both responders (OS rate for surgery vs no surgery: 49% vs 23% [P<.0001] and DPFS rate for surgery vs no surgery: 31% vs 8% [P<.0001]) and nonresponders (OS rate for surgery vs no surgery: 40% vs 6% [P<.0001] and DPFS rate for surgery vs no surgery: 30% vs 0% [P<.0001]). On multivariate analysis, treatment with surgery plus radiotherapy and response to chemotherapy were found to be significant predictors of better OS and DPFS. Local control at the time of last follow-up was 4-fold more likely in patients who underwent surgery with or without radiotherapy compared with patients who received chemotherapy alone (81% vs 18%; P<.0001). Surgery and response to chemotherapy independently predicted local control on multivariate analysis.

CONCLUSIONS

The results of the current study demonstrate that for select patients with metastatic IBC, multimodality treatment including primary tumor resection may result in better local control and survival. However, a randomized trial is needed to validate these findings.

Optimizing locoregional control and survival for women with breast cancer: a review of current developments in postmastectomy radiotherapy

For women who opt for mastectomy as primary surgery in breast cancer, indications for adjuvant radiotherapy are also being redefined in light of evidence demonstrating that postmastectomy radiotherapy (PMRT), when given in conjunction with systemic therapy, improves, not only locoregional control, but also survival. However, in certain settings, particularly in patients wih intermediate-risk disease, and in some patients treated with neoadjuvant chemotherapy, the role of PMRT remains controversial. Here, the authors review modern data pertaining to the benefits and risks of PMRT and discuss controversies related to the indications for PMRT, focusing on patients with T1-2 breast cancer with 0-3 positive nodes and patients treated with neoadjuvant chemotherapy. They also summarize key issues related to the integration of PMRT with other treatment modalities.

High serum miR-19a levels are associated with inflammatory breast cancer and are predictive of favorable clinical outcome in patients with metastatic HER2+ inflammatory breast cancer

INTRODUCTION

Altered serum microRNA (miRNA) levels may be correlated with a dysregulated expression pattern in parental tumor tissue and reflect the clinical evolution of disease. The overexpression of miR-21, miR-10b, and miR-19a is associated with the acquisition of malignant characteristics (increased tumor cell proliferation, migration, invasion, dissemination, and metastasis); thus, we determined their utility as serum biomarkers for aggressive breast cancer (HER2-overexpressed or -amplified [HER2(+)] and inflammatory breast cancer [IBC]).

EXPERIMENTAL DESIGN

In this prospective study, we measured miR-21, miR-10b, and miR-19a levels using quantitative reverse transcriptase-polymerase chain reaction in the serum of 113 breast cancer patients and determined their association with clinicopathologic factors and clinical outcome. Thirty healthy donors with no history of cancer were enrolled as controls.

RESULTS

Patients with non-metastatic HER2(+) breast cancer had higher serum miR-21 median levels than patients with non-metastatic HER2(-) disease (p = 0.044); whereas patients with metastatic HER2(+) breast cancer had higher serum miR-10b median levels than patients with metastatic HER2(-) disease (p = 0.0004). There were no significant differences in serum miR-19a median levels between HER2(+) and HER2(-) groups, regardless of the presence of metastases. High serum miR-19a levels were associated with IBC (p = 0.039). Patients with metastatic IBC had significantly higher serum miR-19a median levels than patients with metastatic non-IBC (p = 0.019). Finally, high serum miR-19a levels were associated with longer progression-free survival time (10.3 vs. 3.2 months; p = 0.022) and longer overall survival time (median not reached vs. 11.2 months; p = 0.003) in patients with metastatic HER2(+) IBC.

CONCLUSION

High levels of miR-21 and miR-10b were present in the serum of patients with non-metastatic and metastatic HER2(+) breast cancer, respectively. High levels of serum miR-19a may represent a biomarker for IBC that is predictive for favorable clinical outcome in patients with metastatic HER2(+) IBC.

Radiation therapy for inflammatory breast cancer: technical considerations and diverse clinical scenarios

SUMMARY Inflammatory breast cancer (IBC) is associated with unique skin findings at presentation, diffuse spread and poorer outcomes compared with non-IBC. Standard of care when metastatic disease is not present at diagnosis includes neoadjuvant chemotherapy, modified radical mastectomy and postmastectomy radiation. Several retrospective studies have demonstrated reasonable local control using varying aggressive approaches that will be reviewed and technical considerations that will be discussed. In general, the existing contemporary data support an aggressive locoregional approach in IBC. The morbidity of extensive locoregional recurrence in IBC merits aggressive efforts in prevention in high-risk metastatic cases. Our large, single-institutional experience suggests that contralateral disease and extension to second echelon nodal stations may still represent curable disease amenable to aggressive locoregional therapy in some cases. Examining 13 IBC cases where contralateral involved nodal basins were treated with radiotherapy with or without surgery at the time of ipsilateral locoregional therapy, four ER-positive patients presented evidence of disease at the last follow-up. Examining 36 patients with metastatic IBC involving any M1 site who underwent neoadjuvant chemotherapy, modified radical mastectomy and postmastectomy radiotherapy similarly revealed that a long-term status of no evidence of disease is achievable in some M1 IBC patients treated with effective systemic therapy and aggressive locoregional therapy. Actuarial 5-year overall survival in this M1 cohort was 54%. Radiotherapy for clinical circumstances including extended regional (M1) disease, palliation of diffuse skin metastases, reirradiation and inoperable IBC will be discussed.

Long-term treatment efficacy in primary inflammatory breast cancer by hormonal receptor- and HER2-defined subtypes

BACKGROUND

Subtypes defined by hormonal receptor (HR) and HER2 status have not been well studied in inflammatory breast cancer (IBC). We characterized clinical parameters and long-term outcomes, and compared pathological complete response (pCR) rates by HR/HER2 subtype in a large IBC patient population. We also compared disease-free survival (DFS) and overall survival (OS) between IBC patients who received targeted therapies (anti-hormonal, anti-HER2) and those who did not.

PATIENTS AND METHODS

We retrospectively reviewed the records of patients diagnosed with IBC and treated at MD Anderson Cancer Center from January 1989 to January 2011. Of those, 527 patients had received neoadjuvant chemotherapy and had available information on estrogen receptor (ER), progesterone receptor (PR), and HER2 status. HR status was considered positive if either ER or PR status was positive. Using the Kaplan-Meier method, we estimated median DFS and OS durations from the time of definitive surgery. Using the Cox proportional hazards regression model, we determined the effect of prognostic factors on DFS and OS. Results were compared by subtype.

RESULTS

The overall pCR rate in stage III IBC was 15.2%, with the HR-positive/HER2-negative subtype showing the lowest rate (7.5%) and the HR-negative/HER2-positive subtype, the highest (30.6%). The HR-negative, HER2-negative subtype (triple-negative breast cancer, TNBC) had the worst survival rate. HR-positive disease, irrespective of HER2 status, had poor prognosis that did not differ from that of the HR-negative/HER2-positive subtype with regard to OS or DFS. Achieving pCR, no evidence of vascular invasion, non-TNBC, adjuvant hormonal therapy, and radiotherapy were associated with longer DFS and OS.

CONCLUSIONS

Hormone receptor and HER2 molecular subtypes had limited predictive and prognostic power in our IBC population. All molecular subtypes of IBC had a poor prognosis. HR-positive status did not necessarily confer a good prognosis. For all IBC subtypes, novel, specific treatment strategies are needed in the neoadjuvant and adjuvant settings.

Abstract ES07-2: Inflammatory breast cancer: Diagnosis, treatment and biology

Inflammatory breast cancer (IBC) is a relatively rare variant of breast cancer accounting for a disproportionate amount of breast cancer mortality. It is histopathologically similar to non-IBC but presents with a very distinct clinical picture: rapid onset of breast redness and swelling often without an obvious lump. Misdiagnosis and delay in diagnosis are common. Although the breast appears “inflamed” obvious inflammatory infiltrates are not detectable in most tissues. Three presentations will focus on the diagnostic challenges, determinants, epidemiology, management and biology of inflammatory breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr ES07-2.

Abstract P6-12-02: Survival differences between patients with metastatic inflammatory and non-inflammatory breast cancer

Background: Very little is known about the survival of patients with inflammatory breast cancer (IBC) and distant metastasis. Furthermore, the American Joint Committee on Cancer classification of breast cancer does not recognize metastatic IBC as a distinct entity within stage IV. We hypothesized that the survival of patients with IBC and distant metastasis is worse than the survival of patients with stage-matched non-IBC.

Patients and Methods: We retrospectively reviewed 5314 consecutive patients with stage III or IV breast cancer (IBC or non-IBC) who were treated at our institution between 1986 and 2012. A total of 1079 patients presented with IBC (stage III: 861; stage IV: 218) and 4235 non-IBC (stage III: 2781; stage IV: 1454). We compared the time to distant metastasis from initial diagnosis, distant metastasis–free survival (DMFS), and overall survival (OS) in stage-matched patients with IBC or non-IBC.

Results: The median follow-up periods were 3.3 years for patients with stage III disease (range, 0-32.2 years) and 1.8 years for patients with stage IV disease (range, 0-19.9 years). The total number of recorded events (metastasis/death) was 1657 for stage III, while the numbers of deaths for stage III and IV were 1337 and 973, respectively. In patients with stage III, the time to distant metastasis was shorter in IBC than in non-IBC (median 1.3 vs. 1.7 years, P &lt; .001). DMFS and OS were shorter in patients with stage III IBC than in those with stage III non-IBC (2.5 vs. 6.9 years, P &lt; .001; and 4.7 vs. 8.9 years, P &lt; .001; respectively). However, there was no significant difference in OS after development of distant metastasis between stage III IBC and non-IBC (median for both 1.3 years, P = .83). In multivariate analysis, the diagnosis of IBC remained significantly associated with mortality after adjusting for potential confounders. De novo stage IV IBC presented more frequently with multiple sites of metastasis than de novo stage IV non-IBC (P = .02). In patients with de novo stage IV disease, OS was shorter in IBC than in non-IBC (2.3 vs. 3.4 years, P = .004). In the multicovariate Cox model, while ethnicity, tumor grade, hormone receptor status and HER2 status, site of metastasis, number of sites of metastasis, and definitive breast surgery by 1 year were all significant factors in OS for stage IV breast cancer, the diagnosis of IBC conferred a hazard ratio of 1.33 (95% confidence interval: 1.05 - 1.69) in multivariate analysis.

Conclusion: Our findings suggest that IBC patients with metastasis at diagnosis have worse outcomes than stage-matched non-IBC patients. IBC patients presenting with de novo stage IV disease should be considered as a separate subcategory of stage IV in the tumor-node-metastasis classification because their clinical course and prognosis are different from those of patients with stage IV non-IBC.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-12-02.

Abstract P6-12-04: Risk factors for inflammatory breast cancer

Background: The 5-year survival rates for inflammatory breast cancer (IBC) are significantly lower than non-IBC, highlighting the importance of cancer prevention in IBC. We investigated the risk factors for IBC subtypes based on estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor 2 (HER2neu) status to determine distinct etiological pathways. The Morgan Welch Inflammatory Breast Cancer Research Program and Clinic at University of Texas MD Anderson Cancer Center (UTMDACC) treats the largest number of IBC patients in a single center. The center maintains a prospective, comprehensive epidemiology registry, through which we were able to conduct the largest single center case-control study on IBC. Methods: We identified 246 patients diagnosed with IBC using strict consensus criteria and 397 cancer free patients seen at the UTMDACC Dan L. Duncan Cancer prevention clinic. We used logistic regression to estimate the odds ratios (OR) and 95% confidence intervals (CI) for the associations between breast cancer reproductive and lifestyle risk factors and IBC tumor subtypes. The tumor subtypes of IBC patients were classified as ER-positive (ER+/PR+/Her2neu-), Her2neu-positive (Her2neu+) and triple negative (ER-/PR-/Her2neu-). Results: In age-adjusted univariate analysis, body mass index (BMI), history of smoking, number of children, age at first pregnancy, breastfeeding, menopausal status, and first degree family history of breast cancer were statistically significant associated with risk of IBC (p&lt;0.05). In multivariable analysis of IBC tumor subtypes, compared to cancer free controls, patients with triple negative (OR = 3.73, 95% CI = 1.52 – 9.13) and Her2neu-positive (OR = 19.27, CI = 4.14 – 89.62) tumors were significantly more likely to have ≥ 2 vs 0-1 children. Patients with triple negative (OR = 0.19, 95% CI = 0.09 – 0.45) and ER-positive (OR = 0.42, CI = 0.19 – 0.88) tumors were significantly less likely to have a history of breastfeeding. Patients with ER-positive (OR = 5.02, CI = 2.29 – 10.99) tumors were also significantly more likely to have a history of smoking. Patients with triple negative (OR = 6.07, CI = 2.62 – 17.07), ER-positive (OR = 7.22, CI = 2.94 – 17.78) and Her2neu-positive (OR = 12.81, CI = 4.59 – 35.78) were more likely to be overweight or obese (BMI ≥ 25kg/m2). Conclusion: The associations identified suggest that overweight or obese status is an important modifiable risk factor for all IBC subtypes. Triple negative IBC share similar risk factors as non-IBC triple negative tumors with increasing number of children and lack of breastfeeding associated with increased risk. Interestingly lack of breastfeeding was also associated with ER-positive IBC tumors, and Her2neu-positive IBC tumors were associated with increasing number of children; two associations that have not been previously reported. Impact: These results highlight the importance of evaluating epidemiologic risk factors of IBC, which could lead to the identification of subtype specific prevention strategies.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-12-04.

Abstract P5-14-08: Prospective phase II study of concurrent capecitabine and radiation demonstrates futility in triple negative chemo-resistant breast cancer

Background: Capecitabine is an established radiosensitizer in rectal and other cancers. We conducted a prospective single arm phase II study to examine the response rate of gross chemo-refractory breast cancer treated with concurrent capecitabine and radiotherapy.

Methods: Patients who had inoperable or marginally operable gross disease in the breast and/or lymph node(s) after chemotherapy or gross disease on the chest wall or in the regional lymphatics after mastectomy were eligible. Patients 1-9 received capecitabine 825 mg/m2 BID daily beginning on the first day of radiotherapy. Excess grade 3 toxicity (%) was observed; the protocol was amended and subsequent patients received drug only on radiation treatment days. Radiation dose was at the discretion of the treating physician (50Gy-72 Gy, with no more than 2.5 Gy/fraction). Response was assessed by a single physician using paired radiation planning CTs (pretreatment and on-treatment after 45 Gy). Clinical correlation to all other available imaging was also made. Kaplan-Meier curves were used to estimate overall survival (OS) and local recurrence-free survival (LRFS). Circulating tumor cells (CTCs) in blood were examined in consenting patients.

Results: The trial was stopped early after an unplanned interim analysis prompted by slow accrual suggested futility independent of response. From 2009-2012, 32 patients were accrued; 26 completed protocol specific treatment (17 post-mastectomy radiation with gross nodes, 4 pre-op, 5 aggressive palliation) and are included in this analysis. Median follow up was 7.3 months (interquartile range 6.7 – 17.4). Nineteen patients (73%) had a partial or complete response. Fourteen patients (53.9%) experienced at least one grade 3 non-dermatitis toxicity including 7/9 treated with continuous dosing. Four inoperable patients were treated with pre-op radiation therapy and 3 converted to operable. None achieved a pCR or near pCR. One-year actuarial OS was 52%. There was no difference in OS comparing among PMRT vs. preoperative or palliative RT (P = 0.90). One-year actuarial local recurrence free survival among PMRT patients was 38%. Ten patients had triple negative (TN) receptor status. There was no difference in radiation response by receptor status (P = 0.56); however, treatment was deemed subjectively futile (i.e., converted to operable but death secondary to new widespread M1 disease immediately post-op) in 9 of the 10 patients with TN disease versus 6 of the 16 patients with non-TN disease (P = 0.014). Median OS and 1-yr actuarial OS, among non-TN vs. TN patients were not reached vs. 6.1 months and 77% vs. 10% (P &lt; 0.001), respectively. Eight/fifteen patients tested were positive for CTCs. CTCs did not correlate to receptor status, futility of RT or OS.

Conclusions: Capecitabine can be safely administered as a daily concurrent chemoradiation regimen with weekend holidays. However, in this small, prospective and selected cohort, concurrent chemoradiation with capecitabine was futile among patients with TN breast cancer. Alternative strategies are urgently needed in TN patients.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-14-08.

Abstract P1-06-07: Immune-induced epithelial to mesenchymal transition in inflammatory breast cancer induces unique increases in E-cadherin, adhesion and migration through TNF-a, IL-6 and TGF-b

BACKGROUND AND RATIONALE

Inflammatory breast cancer (IBC) is the most aggressive form of breast cancer and patients frequently present with metastases at the time of their diagnosis. Although a robust IBC-specific molecular signature remains elusive, the disease is frequently characterized by persistent expression of the adhesion molecule, E-cadherin. This is highly counterintuitive as epithelial to mesenchymal transition (EMT), frequently associated with metastasis, results in decreased E-cadherin expression and highly aggressive cancers frequently express low levels of E-cadherin.

We hypothesized that persistent inflammation, mediated by immune activation, increases the plasticity of IBC cells, inducing EMT and allowing the re-acquisition of epithelia characteristics once removed from the inflammatory foci. In support of this hypothesis, previous in vitro work showed that soluble factors from activated immune cells induce EMT-related transcripts in both IBC and non-IBC cell lines. However, uniquely in 3 of 4 IBC cell lines but none of the non-IBC cell lines, this program included an increase of E-cadherin expression.

RESULTS

We used real-time cell analysis (RTCA) from Acea Biosciences (San Diego, CA) to probe the effect of immune conditioned media, produced by stimulating healthy donor peripheral blood mononuclear cells through the T-cell receptor or through toll-like receptor-4, on SUM149 inflammatory breast cancer cells. Consistent with the increased expression of E-cadherin, we observed rapid and strong increases in cellular adhesion as measured by the RCTA cell-index following culture with immune inflammatory factors. However, using the CIM chip, the same cells also showed strong increases in invasion and migration.

To determine the inflammatory factors involved in this process, we screened the immune conditioned media using a Luminex array (Millipore, Billerica, MA). TGF-b, TNF-α, and IL-6, previously shown to induce EMT, were all found at elevated levels. In 5 culture supernatants of healthy donor PBMC activated for 48h with anti-CD3 antibody, TGF-β had a modest 1.6-fold increase; TNF-α had an average 101-fold increase; while IL-6 had an average 347-fold increase. When added to cultures of SUM149 cells, these factors recapitulated the EMT gene expression signature in SUM149 including the increase in E-cadherin expression. Furthermore, the addition of neutralizing antibodies against TNF-α, TGF-β, and IL-6 to immune conditioned media prior to exposure to SUM149 cells resulted in less EMT.

CONCLUSIONS

Inflammatory factors may induce both the migratory ability and the characteristic persistent E-cadherin expression of IBC cells. This is mediated in part by TNF-α, TGF-β, and IL-6. However, the molecular basis for this unique IBC response requires further study hindering the development of optimal therapies. Ongoing studies at MD Anderson are exploring both the tumor and stromal components of inflammatory breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-06-07.

Human omental-derived adipose stem cells increase ovarian cancer proliferation, migration, and chemoresistance

Objectives

Adipose tissue contains a population of multipotent adipose stem cells (ASCs) that form tumor stroma and can promote tumor progression. Given the high rate of ovarian cancer metastasis to the omental adipose, we hypothesized that omental-derived ASC may contribute to ovarian cancer growth and dissemination.

Materials and Methods

We isolated ASCs from the omentum of three patients with ovarian cancer, with (O-ASC4, O-ASC5) and without (O-ASC1) omental metastasis. BM-MSCs, SQ-ASCs, O-ASCs were characterized with gene expression arrays and metabolic analysis. Stromal cells effects on ovarian cancer cells proliferation, chemoresistance and radiation resistance was evaluated using co-culture assays with luciferase-labeled human ovarian cancer cell lines. Transwell migration assays were performed with conditioned media from O-ASCs and control cell lines. SKOV3 cells were intraperitionally injected with or without O-ASC1 to track in-vivo engraftment.

Results

O-ASCs significantly promoted invitro proliferation, migration chemotherapy and radiation response of ovarian cancer cell lines. O-ASC4 had more marked effects on migration and chemotherapy response on OVCA 429 and OVCA 433 cells than O-ASC1. Analysis of microarray data revealed that O-ASC4 and O-ASC5 have similar gene expression profiles, in contrast to O-ASC1, which was more similar to BM-MSCs and subcutaneous ASCs in hierarchical clustering. Human O-ASCs were detected in the stroma of human ovarian cancer murine xenografts but not uninvolved ovaries.

Conclusions

ASCs derived from the human omentum can promote ovarian cancer proliferation, migration, chemoresistance and radiation resistance in-vitro. Furthermore, clinical O-ASCs isolates demonstrate heterogenous effects on ovarian cancer in-vitro.

Gene expression profiles of inflammatory breast cancer: correlation with response to neoadjuvant chemotherapy and metastasis-free survival

BACKGROUND

Inflammatory breast cancer (IBC) is an aggressive disease. To date, no molecular feature reliably predicts either the response to chemotherapy (CT) or the survival. Using DNA microarrays, we searched for multigene predictors.

PATIENTS AND METHODS

The World IBC Consortium generated whole-genome expression profiles of 137 IBC and 252 non-IBC (nIBC) samples. We searched for transcriptional profiles associated with pathological complete response (pCR) to neoadjuvant anthracycline-based CT and distant metastasis-free survival (DMFS) in respective subsets of 87 and 106 informative IBC samples. Correlations were investigated with predictive and prognostic gene expression signatures published in nIBC (nIBC-GES). Supervised analyses tested genes and activation signatures of 19 biological pathways and 234 transcription factors.

RESULTS

Three of five tested prognostic nIBC-GES and the two tested predictive nIBC-GES discriminated between IBC with and without pCR, as well as two interferon activation signatures. We identified a 107-gene signature enriched for immunity-related genes that distinguished between responders and nonresponders in IBC. Its robustness was demonstrated by external validation in three independent sets including two IBC sets and one nIBC set, with independent significant predictive value in IBC and nIBC validation sets in multivariate analysis. We found no robust signature associated with DMFS in patients with IBC, and neither of the tested prognostic GES, nor the molecular subtypes were informative, whereas they were in our nIBC series (220 stage I-III informative samples).

CONCLUSION

Despite the relatively small sample size, we show that response to neoadjuvant CT in IBC is, as in nIBC, associated with immunity-related processes, suggesting that similar mechanisms responsible for pCR exist. Analysis of a larger IBC series is warranted regarding the correlation of gene expression profiles and DMFS.

Comparison of molecular subtype distribution in triple-negative inflammatory and non-inflammatory breast cancers

Introduction

Because of its high rate of metastasis, inflammatory breast cancer (IBC) has a poor prognosis compared with non-inflammatory types of breast cancer (non-IBC). In a recent study, Lehmann and colleagues identified seven subtypes of triple-negative breast cancer (TNBC). We hypothesized that the distribution of TNBC subtypes differs between TN-IBC and TN-non-IBC. We determined the subtypes and compared clinical outcomes by subtype in TN-IBC and TN-non-IBC patients.

Methods

We determined TNBC subtypes in a TNBC cohort from the World IBC Consortium for which IBC status was known (39 cases of TN-IBC; 49 cases of TN-non-IBC). We then determined the associations between TNBC subtypes and IBC status and compared clinical outcomes between TNBC subtypes.

Results

We found the seven subtypes exist in both TN-IBC and TN-non-IBC. We found no association between TNBC subtype and IBC status (P = 0.47). TNBC subtype did not predict recurrence-free survival. IBC status was not a significant predictor of recurrence-free or overall survival in the TNBC cohort.

Conclusions

Our data show that, like TN-non-IBC, TN-IBC is a heterogeneous disease. Although clinical characteristics differ significantly between IBC and non-IBC, no unique IBC-specific TNBC subtypes were identified by mRNA gene-expression profiles of the tumor. Studies are needed to identify the subtle molecular or microenvironmental differences that contribute to the differing clinical behaviors between TN-IBC and TN-non-IBC.

Abstract B73: Human omental-derived adipose stem cells: Modulator of ovarian cancer proliferation, migration and chemoresistance

Objectives: Adipose tissue contains a population of multipotent mesenchymal stromal cells (ASC) which exhibit tumor tropism, similar to bone marrow derived mesenchymal stem cells (MSC). Excess visceral adipose tissue increases the risk of ovarian cancer. The omentum is a prominent site for ovarian cancer metastasis. We hypothesize that the omentum serves as a source of ASC which promote ovarian cancer progression.

Materials and Methods: ASC were isolated from the omentum (O-ASCs) of three patients with ovarian cancer. O-ASC1 was isolated from a patient with synchronous adenocarcinoma of endometrial and ovarian cancer without peritoneal metastasis; and O-ASC4 and O-ASC5 were isolated from patients with peritoneally disseminated serous ovarian cancer. Gene expression array profiling was performed with using Nimblegen arrays (Roche NimbleGen, Inc., Madison, WI). The impact of stromal cells on proliferation and chemoresistane and radio-protection of ovarian cancer cells was tested with co-culture assays using luciferase-labeled human ovarian cancer cell lines. Transwell migration assays were performed with conditioned media from O-ASC and control cell lines. To evaluate of O-ASCs tumor tropism in-vivo experiment was performed.

Results: Human O-ASCs were detected engrafted within the stroma of human ovarian cancer xengrafts. O-ASC significantly promoted in-vitro proliferation and migration of ovarian cancer cell lines OVCA 429, OVCA 433, A2780. Co-culture of ovarian cancer cells with O-ASCs increased resistance to chemotherapeutic drugs and radiation. Gene expression array analysis revealed significant differences in expression profiles for group of 415 genes in sub-populations of O-ASCs.

Conclusions: Adipose stem cells derived from human omentum promoted the proliferation, migration, chemoresistance and radioresistance of ovarian cancers. Clinical isolates demonstrate heterogenous effects in- vitro. Future studies will determine if tumor promoting effects of O-ASC can be predicted on the basis of clinical or disease related characteristics.

Citation Format: Aleksandra Nowicka, Travis Solley, Frank C. Marini, Hadley J. Sharp, Russell R. Broaddus, Kolonin G. Mikhail, Samuel C. Mok, Wendy A. Woodward, Karen H. Lu, Ann H. Klopp. Human omental-derived adipose stem cells: Modulator of ovarian cancer proliferation, migration and chemoresistance. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr B73.

Receptor status change from primary to residual breast cancer after neoadjuvant chemotherapy (NCT) and analysis of survival outcome

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Background: Treatment and prognosis of breast cancer is determined by tumor subtype. Tumor heterogeneity and lack of stability in ER, PR and HER2 has been described. We evaluated the changes receptor status between primary and residual disease after NCT and its association with outcome. Methods: 398 women with known ER, PR and HER2 status in primary and residual disease were identified. Patients were classified as no receptor change vs. any receptor change. For ER and PR we explored absolute percent changes. Descriptive statistics were used. Kaplan-Meier method was used to estimate overall (OS) and recurrence-free (RFS) survival. Cox proportional models were fit to determine the association of receptor status changes with outcomes after adjustment for patient and disease characteristics. Results: From the 398 patients, 162 (40.7%) had a change in at least one biomarker. Twenty-three (10.9%) of the 211 ER-positive tumors changed to ER-negative and 39 (20.8%) of the 187 ER-negative tumors changed to ER-positive. Fifty-seven (35.2%) of the 162 PR-positive tumors changed to PR-negative and 28 (11.9%) of the 235 PR-negative tumors changed to PR-positive. Lastly, 29 (40%) of the 72 HER2-positive tumors changed to HER2-negative and among the 35 trastuzumab-treated patients, 16 (45.7%) had HER2 status changed. At a median follow up of 40 months, 128 women (32%) had died, and 167 (41.8%) had experienced a recurrence. Five-year OS estimates were 73% and 63% for patients with or without any receptor change, (P=0.07); 5-year RFS estimates were 63% and 48% for patients with or without any receptor change, (P=0.003). Among patients with baseline ER-positive tumors, 5-year OS estimates was 73% and 87% (P=0.03), and the 5-year RFS estimates was 59% and 71% (P=0.03) for those whose absolute ER percent decrease was less than 20% or more than 20%, respectively. A change in any receptor was associated with better RFS (HR: 0.63, 95% CI 0.44-0.9) but not with OS, (HR: 0.79, 95% CI 0.53-1.18). Conclusions: Changes in ER, PR and HER2 status between the primary and the residual disease after neoadjuvant chemotherapy are frequent. In this study, a change in biomarker status was associated with significant improved RFS.

TIG1 promotes the development and progression of inflammatory breast cancer through activation of Axl kinase

Inflammatory breast cancer (IBC) is the most lethal form of breast cancer, but the basis for its aggressive properties are not fully understood. In this study, we report that high tumoral expression of TIG1 (RARRES1), a functionally undefined membrane protein, confers shorter survival in patients with IBC. TIG1 depletion decreased IBC cell proliferation, migration, and invasion in vitro and inhibited tumor growth of IBC cells in vivo. We identified the receptor tyrosine kinase, Axl, as a TIG1-binding protein. TIG1 interaction stablilized Axl by inhibiting its proteasome-dependent degradation. TIG1-depleted IBC cells exhibited reduced Axl expression, inactivation of NF-κB, and downregulation of matrix metalloproteinase-9, indicating that TIG1 regulates invasion of IBC cells by supporting the Axl signaling pathway in IBC cells. Consistent with these results, treatment of IBC cells with the Axl inhibitor SGI-7079 decreased their malignant properties in vitro. Finally, TIG1 expression correlated positively with Axl expression in primary human IBC specimens. Our findings establish that TIG1 positively modifies the malignant properties of IBC by supporting Axl function, advancing understanding of its development and rationalizing TIG1 and Axl as promising therapeutic targets in IBC treatment.

Accelerated partial-breast irradiation using intensity-modulated proton radiotherapy: do uncertainties outweigh potential benefits?

OBJECTIVE

Passive scattering proton beam (PSPB) radiotherapy for accelerated partial-breast irradiation (APBI) provides superior dosimetry for APBI three-dimensional conformal photon radiotherapy (3DCRT). Here we examine the potential incremental benefit of intensity-modulated proton radiotherapy (IMPT) for APBI and compare its dosimetry with PSPB and 3DCRT.

METHODS

Two theoretical IMPT plans, TANGENT_PAIR and TANGENT_ENFACE, were created for 11 patients previously treated with 3DCRT APBI and were compared with PSPB and 3DCRT plans for the same CT data sets. The impact of range, motion and set-up uncertainties as well as scanned spot mismatching between fields of IMPT plans was evaluated.

RESULTS

IMPT plans for APBI were significantly better regarding breast skin sparing (p<0.005) and other normal tissue sparing than 3DCRT plans (p<0.01) with comparable target coverage (p=ns). IMPT plans were statistically better than PSPB plans regarding breast skin (p<0.002) and non-target breast (p<0.007) in higher dose regions but worse or comparable in lower dose regions. IMPT plans using TANGENT_ENFACE were superior to that using TANGENT_PAIR in terms of target coverage (p<0.003) and normal tissue sparing (p<0.05) in low-dose regions. IMPT uncertainties were demonstrated for multiple causes. Qualitative comparison of dose-volume histogram confidence intervals for IMPT suggests that numeric gains may be offset by IMPT uncertainties.

CONCLUSION

Using current clinical dosimetry, PSPB provides excellent dosimetry compared with 3DCRT with fewer uncertainties compared with IMPT.

ADVANCES IN KNOWLEDGE

As currently delivered in the clinic, PSPB planning for APBI provides as good or better dosimetry than IMPT with less uncertainty.

The antihelmintic drug pyrvinium pamoate targets aggressive breast cancer

WNT signaling plays a key role in the self-renewal of tumor initiation cells (TICs). In this study, we used pyrvinium pamoate (PP), an FDA-approved antihelmintic drug that inhibits WNT signaling, to test whether pharmacologic inhibition of WNT signaling can specifically target TICs of aggressive breast cancer cells. SUM-149, an inflammatory breast cancer cell line, and SUM-159, a metaplastic basal-type breast cancer cell line, were used in these studies. We found that PP inhibited primary and secondary mammosphere formation of cancer cells at nanomolar concentrations, at least 10 times less than the dose needed to have a toxic effect on cancer cells. A comparable mammosphere formation IC50 dose to that observed in cancer cell lines was obtained using malignant pleural effusion samples from patients with IBC. A decrease in activity of the TIC surrogate aldehyde dehydrogenase was observed in PP-treated cells, and inhibition of WNT signaling by PP was associated with down-regulation of a panel of markers associated with epithelial-mesenchymal transition. In vivo, intratumoral injection was associated with tumor necrosis, and intraperitoneal injection into mice with tumor xenografts caused significant tumor growth delay and a trend toward decreased lung metastasis. In in vitro mammosphere-based and monolayer-based clonogenic assays, we found that PP radiosensitized cells in monolayer culture but not mammosphere culture. These findings suggest WNT signaling inhibition may be a feasible strategy for targeting aggressive breast cancer. Investigation and modification of the bioavailability and toxicity profile of systemic PP are warranted.

Clinical relevance of cancer stem cells in bone marrow of early breast cancer patients

BACKGROUND

Cancer stem cells (CSCs) are epithelial tumor cells that express CD44(+)CD24(-/lo). CSCs can be further divided into those that have aldehyde dehydrogenase (ALDH) activity (Aldefluor(+)) and those that do not. We hypothesized that if CSCs are responsible for tumor dissemination, their presence in bone marrow (BM) would be prognostic in early stages of breast cancer (EBC) patients.

PATIENTS AND METHODS

BM aspirates were collected at the time of surgery from 108 patients with EBC. BM was analyzed for CSCs and ALDH activity by flow cytometry. Overall survival and disease-free survival (DFS) were calculated from the date of diagnosis and analyzed with Kaplan-Meier survival plots. Cox multivariate proportional hazards model was also carried out.

RESULTS

Patients with CSCs in BM had a hazard ratio (HR) of 8.8 for DFS (P = 0.002); patients with Aldefluor(+) CSCs had a HR of 5.9 (P = 0.052) for DFS. All deceased patients (n = 7) had CSCs in BM. In multivariate analysis, the presence of CSCs in BM was a prognostic factor of DFS (HR = 15.8, P = 0.017).

CONCLUSIONS

The presence of BM metastasis is correlated with CSCs and these CSCs irrespective of ALDH activity are an independent adverse prognostic factor in EBC patients.

Abstract 1600: Simvastatin targets breast cancer stem-like cells by inhibiting intracellular signaling pathways leading to radiosensitization of inflammatory breast cancer cells

Background: Inflammatory breast cancer (IBC) is responsible for 10% of breast cancer deaths although contributing to a small percentage (∼1%) of total breast cancer cases each year. The hallmarks of IBC are skin involvement and a high propensity to metastasize. It is thought that a small population of stem-like cancer cells is responsible for the metastatic potential and treatment resistance to therapies such as radiation therapy in IBC. In this study we explored the radiosensitization of several breast cancer cell lines in vitro with simvastatin and the mechanism for this.

Methods: In order to determine cell proliferation, breast cancer cell lines SUM149, SUM159 and MCF-7 were grown in 96 well plates with different concentrations of simvastatin for one week. In order to determine the effect of simvastatin in stem-like cancer cells, cells were seeded in serum free, growth factor enriched, anchorage independent, treated with simvastatin for 24 hours and mammosphere formation was quantified a week later. In addition, SUM149, SUM159 and MCF-7 cells were cultured in standard monolayer cultures and in stem cell enriching anchorage independent cultures with simvastatin and treated with increasing concentrations of radiation. Survival curves were generated using Sigmaplot 8.0 and t-test was used to compare surviving fraction (SF) of groups. Finally, cell lysates were obtained from cultures untreated and treated with simvastatin and radiation and analyzed through western blot.

Results: Simvastatin significantly decreased cancer cell proliferation in vitro in all cell lines (p&lt;0.002). Cell lines SUM 159 and MCF 7 grown in mammosphere enriched media showed significant decreased mammosphere formation when grown in the presence of simvastatin (p&lt;0.05). Moreover, simvastatin radiosensitized all cell lines in both monolayer and anchorage independent clonogenic assays. The triple-negative IBC cell line SUM149 had the greatest response to combined treatment regardless of the radiation dose used in monolayer cultures (SF2: 0.417 vs 0.319, SF4: 0.136 vs 0.075, SF6: 0.026 vs 0.018, in control vs treated respectively, all p&lt;0.0001) and in stem cell enriching cultures (SF2: 0.880 vs 0.762, SF4: 0.863 vs 0.492, SF6: 0.920 vs 0.492, in control vs treated respectively, all p&lt;0.0001). The triple-negative non-IBC cell line SUM159 was more sensitive to combined treatment in monolayer cultures (p&lt;0.001) than in stem cell enriching cultures. Combination of simvastatin and radiation therapy decreased protein expression of phospho-rho A, VEGF-A, and phospho-ras.

Conclusions: IBC remains a difficult disease to treat with a high rate of local recurrence after radiation therapy. Statins have been shown to increase tumor free survival in breast cancer. Herein we show simvastatin targets breast cancer stem-like cells resulting in radiosensitizing of IBC in vitro.

Citation Format: Adam R. Wolfe, Lara Lacerda, Richard Larson, Bisrat G. Debeb, Wei Xu, Naoto T. Ueno, Wendy A. Woodward. Simvastatin targets breast cancer stem-like cells by inhibiting intracellular signaling pathways leading to radiosensitization of inflammatory breast cancer cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1600. doi:10.1158/1538-7445.AM2013-1600

Abstract 3051: The miR-200 family as a potential therapeutic target in inflammatory breast cancer

Purpose: Inflammatory breast cancer (IBC) is the most lethal, aggressive variant of breast cancer characterized by rapid progression, local and distant metastases, younger age of onset, and poor overall survival. Despite advances in multimodal breast cancer care, no IBC specific therapy is available clinically, demonstrating a critical need to identify novel therapeutics that target the distinct biology of IBC. MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression and have been implicated as potential therapeutic targets. Although the oncogenic or tumor-suppressor functions of a large number of miRNAs have been described in various solid tumors including breast cancer, the role of miRNAs in the biology of IBC is poorly understood. Herein, we investigated miRNAs differentially expressed in IBC, particularly miR-200 family miRNAs as potential therapeutic targets in IBC.

Methods: MicroRNA microarray profiling was conducted in IBC and non-IBC cell lines, and microarray results were validated using qRT-PCR. MirZip lentiviral based mirRNA inhibition was used to stably knockdown miRNAs and the effects of specific miRNA knockdown on proliferation, EMT, colony and mammosphere formation was evaluated. For tumor progression and metastasis in vivo experiments, we injected 500,000 SUM149 miR-200a, miR-141 knockdown and control (N=15 for each group) cells into the cleared mammary fatpad of SCID/Beige mice. We also validated the expression of miR-200 miRNAs in IBC patient samples.

Results: Differential expression of mirRNAs was observed in IBC vs. non-IBC cell lines with a significantly higher expression of all miR-200 family (miR-200a, miR-200b, miR-200c, miR-141 and miR-479) in IBC cell lines. These results were validated using qRT-PCR, with the IBC cell lines showing a &gt;1,000-fold higher expression of miR-200s vs non-IBC aggressive cell lines (P&lt;0.0001). Moreover, two known targets of the miR-200 family, Zeb1 and Zeb2, were significantly downregulated while E-cadherin was upregulated in the IBC samples. Importantly, these observations were validated in IBC patient samples which showed a significantly higher expression of all miRNA 200s compared to the normal breast tissues (P&lt;0.001). In vitro, miR-200a and miR-141 knockdown significantly reduced both colony and mammosphere formation in the triple negative SUM149 cells (P&lt;0.001) but did not have a significant effect on the HER2+ IBC cell lines SUM190 and MDA-IBC-3 (P&gt;0.05) while it upregulated the EMT markers N-cadherin, Fibronectin, TGFβ, and Smad4 and reduced E-cadherin expression compared to transduced controls. In vivo, miR-200 knockdown resulted in an increase in tumor progression vs. controls (P&lt;0.05, Day 63) while metastasis studies are undergoing.

Conclusions: These data suggest that miR-200 family microRNAs play an important role in IBC tumor progression and altering miR-200 levels could be an efficacious approach to target IBC.

Citation Format: Bisrat G. Debeb, Lara Lacerda, Richard Larson, Li Li, Wei Xu, Lei Huo, Caimiao Wei, Savitri Krishnamurthy, James Reuben, Naoto Ueno, Thomas Buchholz, Wendy A. Woodward, Morgan Welch Inflammatory Breast Cancer Research Program and Clinic. The miR-200 family as a potential therapeutic target in inflammatory breast cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3051. doi:10.1158/1538-7445.AM2013-3051

Genomic and expression analysis of microdissected inflammatory breast cancer

Inflammatory breast cancer (IBC) is a unique clinical entity characterized by rapid onset of erythema and swelling of the breast often without an obvious breast mass. Many studies have examined and compared gene expression between IBC and non-IBC (nIBC), repeatedly finding clusters associated with receptor subtype, but no consistent gene signature associated with IBC has been validated. Here we compared microdissected IBC tumor cells to microdissected nIBC tumor cells matched based on estrogen and HER-2/neu receptor status. Gene expression analysis and comparative genomic hybridization were performed. An IBC gene set and genomic set were identified using a training set and validated on the remaining data. The IBC gene set was further tested using data from IBC consortium samples and publicly available data. Receptor driven clusters were identified in IBC; however, no IBC-specific gene signature was identified. Fifteen genes were correlated between increased genomic copy number and gene overexpression data. An expression-guided gene set upregulated in the IBC training set clustered the validation set into two clusters independent of receptor subtype but segregated only 75 % of samples in each group into IBC or nIBC. In a larger consortium cohort and in published data, the gene set failed to optimally enrich for IBC samples. However, this gene set had a high negative predictive value for excluding the diagnosis of IBC in publicly available data (100 %). An IBC enriched genomic data set accurately identified 10/16 cases in the validation data set. Even with microdissection, no IBC-specific gene signature distinguishes IBC from nIBC. Using microdissected data, a validated gene set was identified that is associated with IBC tumor cells. Inflammatory breast cancer comparative genomic hybridization data are presented, but a validated genomic data set that identifies IBC is not demonstrated.

Pathologic complete response to neoadjuvant chemotherapy with trastuzumab predicts for improved survival in women with HER2-overexpressing breast cancer

BACKGROUND

We sought to determine the prognostic value of pathologic response to neoadjuvant chemotherapy with concurrent trastuzumab.

PATIENTS AND METHODS

Two hundred and twenty-nine women with HER2/neu (HER2)-overexpressing breast cancer were treated with neoadjuvant chemotherapy plus trastuzumab between 2001 and 2008. Patients were grouped based on pathologic complete response (pCR, n = 114) or less than pCR (<pCR, n = 115); as well as by pathologic stage. Locoregional recurrence-free (LRFS), distant metastasis-free (DMFS), recurrence-free (RFS), and overall survival (OS) rates were compared.

RESULTS

The median follow-up was 63 (range 53-77) months. There was no difference in clinical stage between patients with pCR or <pCR. Compared with patients achieving <pCR, those with the pCR had higher 5-year rates of LRFS (100% versus 95%, P = 0.011), DMFS (96% versus 80%, P < 0.001), RFS (96% versus 79%, P < 0.001), and OS (95% versus 84%, P = 0.006). Improvements in RFS and OS were seen with decreasing post-treatment stage. Failure to achieve a pCR was the strongest independent predictor of recurrence (hazard ratio [HR] = 4.09, 95% confidence interval [CI]: 1.67-10.04, P = 0.002) and death (HR = 4.15, 95% CI: 1.39-12.38, P = 0.011).

CONCLUSIONS

pCR and lower pathologic stage after neoadjuvant chemotherapy with trastuzumab are the strongest predictors of recurrence and survival and are surrogates of the long-term outcome in patients with HER2-overexpressing disease.

Histone deacetylase inhibitors stimulate dedifferentiation of human breast cancer cells through WNT/β-catenin signaling

Recent studies have shown that differentiated cancer cells can dedifferentiate into cancer stem cells (CSCs) although to date no studies have reported whether this transition is influenced by systemic anti-cancer agents. Valproic acid (VA) is a histone deacetylase (HDAC) inhibitor that promotes self-renewal and expansion of hematopoietic stem cells and facilitates the generation of induced pluripotent stem cells from somatic cells and is currently being investigated in breast cancer clinical trials. We hypothesized that HDAC inhibitors reprogram differentiated cancer cells toward the more resistant stem cell-like state. Two highly aggressive breast cancer cell lines, SUM159 and MDA-231, were sorted based on aldehyde dehydrogenase (ALDH) activity and subsequently ALDH-negative and ALDH-positive cells were treated with one of two known HDAC inhibitors, VA or suberoylanilide hydroxamic acid. In addition, primary tumor cells from patients with metastatic breast cancer were evaluated for ALDH activity following treatment with HDAC inhibitors. We demonstrate that single-cell-sorted ALDH-negative cells spontaneously generated ALDH-positive cells in vitro. Treatment of ALDH-negative cells with HDAC inhibitors promoted the expansion of ALDH-positive cells and increased mammosphere-forming efficiency. Most importantly, it significantly increased the tumor-initiating capacity of ALDH-negative cells in limiting dilution outgrowth assays. Moreover, while HDAC inhibitors upregulated β-catenin expression and significantly increased WNT reporter activity, a TCF4 dominant negative construct abolished HDAC-inhibitor-induced expansion of CSCs. These results demonstrate that HDAC inhibitors promote the expansion of breast CSCs through dedifferentiation and have important clinical implications for the use of HDAC inhibitors in the treatment of cancer.

Uncovering the molecular secrets of inflammatory breast cancer biology: an integrated analysis of three distinct affymetrix gene expression datasets

BACKGROUND

Inflammatory breast cancer (IBC) is a poorly characterized form of breast cancer. So far, the results of expression profiling in IBC are inconclusive due to various reasons including limited sample size. Here, we present the integration of three Affymetrix expression datasets collected through the World IBC Consortium allowing us to interrogate the molecular profile of IBC using the largest series of IBC samples ever reported.

EXPERIMENTAL DESIGN

Affymetrix profiles (HGU133-series) from 137 patients with IBC and 252 patients with non-IBC (nIBC) were analyzed using unsupervised and supervised techniques. Samples were classified according to the molecular subtypes using the PAM50-algorithm. Regression models were used to delineate IBC-specific and molecular subtype-independent changes in gene expression, pathway, and transcription factor activation.

RESULTS

Four robust IBC-sample clusters were identified, associated with the different molecular subtypes (P<0.001), all of which were identified in IBC with a similar prevalence as in nIBC, except for the luminal A subtype (19% vs. 42%; P<0.001) and the HER2-enriched subtype (22% vs. 9%; P<0.001). Supervised analysis identified and validated an IBC-specific, molecular subtype-independent 79-gene signature, which held independent prognostic value in a series of 871 nIBCs. Functional analysis revealed attenuated TGF-β signaling in IBC.

CONCLUSION

We show that IBC is transcriptionally heterogeneous and that all molecular subtypes described in nIBC are detectable in IBC, albeit with a different frequency. The molecular profile of IBC, bearing molecular traits of aggressive breast tumor biology, shows attenuation of TGF-β signaling, potentially explaining the metastatic potential of IBC tumor cells in an unexpected manner.

Radiation dose escalation for loco-regional recurrence of breast cancer after mastectomy

BACKGROUND

Radiation is a standard component of treatment for patients with locoregional recurrence (LRR) of breast cancer following mastectomy. The current study reports the results of a 10% radiation dose escalation in these patients.

METHODS

159 patients treated at MD Anderson Cancer Center between 1994-2006 with isolated LRR after mastectomy alone were reviewed. Patients in the standard treatment group (65 pts, 40.9%) were treated to 50 Gy comprehensively plus a boost of 10 Gy. The dose escalated group (94 pts, 59.1%) was treated to 54 Gy comprehensively and a minimum 12 Gy boost. Median dose in the standard dose and dose escalated group was 60 Gy (±1 Gy, 95% CI) and 66 Gy (±0.5 Gy, 95% CI) respectively. Median follow up for living patients was 94 months from time of recurrence.

RESULTS

The actuarial five year locoregional control (LRC) rate was 77% for the entire study population. The five year overall survival and disease-free survival was 55% and 41%, respectively. On multivariate analysis, initial tumor size (p = 0.03), time to initial LRR (p = 0.03), absence of gross tumor at the time of radiation (p = 0.001) and Her2 status (p = 0.03) were associated with improved LRC. Five year LRC rates were similar in patients with a complete response to chemotherapy without surgery and patients with a complete surgical excision (77% vs 83%, p = NS), compared to a 63% LRC rate in patients with gross disease at the time of radiation (p = 0.024). LRC rates were 80% in the standard dose group and 75% in the dose escalated group (p = NS).

CONCLUSIONS

While LRR following mastectomy is potentially curable, distant metastasis and local control rates remain suboptimal. Radiation dose escalation did not appear to improve LRC. Given significant local failure rates, these patients are good candidates for additional strategies to improve their outcomes.

Abstract P3-10-01: Epidemiological risk factors and normal breast tissue markers in inflammatory breast cancer

Background: Inflammatory breast cancer (IBC) is a rare form of aggressive breast cancer with no existing identifiers for screening or prevention strategies. Women with triple-negative (TNBC, ER–, PR–, Her2–) non-inflammatory breast cancer are less likely to breastfeed, and we have shown in adjacent normal breast tissue that this tissue has more foci of stem cells compared to non-TNBC cancers. A disproportionately higher percentage of women with IBC have TNBC relative to women with non-IBC. We hypothesized that adjacent normal tissue in TNBC IBC vs. TN non-IBC may also display unique biological features based on epidemiologic characteristics.

Methods: We examined epidemiologic factors by breast cancer receptor subtype in 144 patients diagnosed with IBC in 1991–2011 at MD Anderson Cancer Center. Breast cancer risk factors including parity and breastfeeding were compared between patients with TN and non-TN IBC with chi-square or Wilcoxon rank sum tests. Normal adjacent tissues were stained for stem cell markers CD44+CD49f+CD133/2+ and macrophage marker CD68.

Results: The mean age at diagnosis was 52.3 years (range = 23–80) and 83% of patients were non-Hispanic white, 80% were overweight or obese (BMI &gt;25), and 36% were TN IBC. Patients with TN IBC had significantly lower frequency of breastfeeding compared with non-TN IBC, 28% vs. 55%, (p = 0.01). No differences were found in the frequency of other breast cancer risk factors. All 8 IBC adjacent tissue samples showed a distinct spatial distribution of stem cell staining, not limited to the triple negative patients. Compared with 0/60 non-IBC cases, 0/8 triple negative non-IBC, (p = 0.001 Pearson chi-square). Given the high BMI among IBC patients, we further examined normal tissues for the presence of CD68+ cells distributed individually or as clusters exhibiting a “crown-like” pattern (multiple CD 68+ macrophages found around dead adipocytes), and found that 7 of the 8 IBC adjacent tissues were CD68+. Benign biopsies collected from 2 patients at 10 years before diagnosis displayed similar staining, including both stem cell and CD68 staining. Compared with 12/60 non-IBC adjacent tissues were positive for CD68, with 1/8 TN non-IBC, (p = 0.001 Pearson chi-square).

Conclusion: We describe for the first time a stem-cell staining pattern unique to IBC present in all IBC tissues examined, including pre-cancer biopsies. Tissue samples from additional patients will be examined to further explore the relationship between stem cells and CD68 positivity with IBC subtypes.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-10-01.

Abstract PD03-08: Statin use and improved outcome in primary inflammatory breast cancer: retrospective cohort study

Background Inflammatory breast cancer (IBC) is the most aggressive type of breast cancer. HMG-CoA reductase inhibitors (statins) are cholesterol reducing agents with pleiotropic effects, including antitumorigenic and anti-inflammatory properties. We hypothesized that statins reduce the metastatic potential in primary IBC.

Methods We retrospectively reviewed 724 patients diagnosed with and treated for primary IBC at The University of Texas MD Anderson Cancer Center between Jan. 12, 1995 and Jan. 27, 2011. Patients with records indicating statin use at the time of IBC diagnosis on the electronic medical record were compared with those without. We further compared outcomes stratified by statin type (hydrophilic [H] versus lipophilic [L]). We used the Kaplan-Meier method to estimate the median disease-free survival (DFS) after surgery, overall survival (OS), and disease specific survival (DSS), followed by Cox proportional hazards regression model to test statistical significance of several potential prognostic factors.

Results For primary IBC patients who had information on their statin use status at IBC diagnosis, the median DFS time were 4.88 years, 2.47 years and 1.76 years (P= 0.04); the median OS time 5.05 years, 3.79 years and 4.32 years (P= 0.35); and the median DSS time 5.10 years, 3.79 years and 4.52 years (P= 0.37), for patients who took “ H”, “L” and no statin, respectively. In multivariable Cox model stratified by radiation therapy, ER/PR status and HER2 status, statin “H” use was associated with significantly improved DFS compared to no statin use (HR=0.49; 95% CI: 0.28–0.84; p&lt;0.01), adjusted for lymphatic/vascular invasion. Although there is a trend that patients who used statin “H” had a longer time to death compared to patients who did not take statin, it did not reach statistical significance for OS (HR=0.80; 95% CI: 0.43–1.49; p=0.49) and DSS (HR=0.85; 95% CI: 0.46–1.57, p=0.59) after adjustment for lymphatic/vascular invasion, nuclear grade and surgery status within one year.

Conclusions Hydrophilic statin use was associated with improved DFS. There was a trend for reduced HR in OS and DSS among primary IBC patient who used hydrophilic statins. A prospective randomized study to evaluate the potential survival benefits of statins in primary IBC population is warranted.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD03-08.

Abstract P5-03-05: Histone deacetylase (HDAC)-inhibitor mediated reprogramming drives cancer cells to the pentose phosphate metabolic pathway

Recent studies have shown that energy metabolism in human pluripotent cells contrasts sharply with energy metabolism in differentiated cell types. Specifically, it has been shown that nuclear reprogramming from somatic cells to induced pluripotent stem cells is associated with a switch from oxidative to glycolytic metabolism. Whether a metabolic switch also occurs in reprogrammed/dedifferentiated breast cancer cells is unknown. Moreover, the function of the metabolic state in stemness is poorly understood and no data are available on whether breast cancer stem cells (CSCs) are metabolically different from committed cancer cells. Herein we demonstrated that HDAC inhibitors reprogram committed single aldefluor negative breast cancer cells into aldefluor positive cells (10.3 ± 2.8 vs 21.3 ±3.7% untreated vs treated P &lt;0.05, representing an average of 5 single cell derived clones) and promoted tumor initiation from non-initiating committed cells (p = 0.004). Further, induced stem-like cells were resistant to taxol and salinomycin, a drug previously described to target CSCs. These reprogrammed cancer cells have enhanced activity of the pentose phosphate pathway (PPP) with upregulation of G6PD expression and activity and higher levels of NADPH and ROS. Hypothesizing that CSCs may favor the PPP in order to survive and self renew, we used G6PD inhibitors, 6-AN and Imatinib, to target mammosphere formation and aldefluor activity in HDAC inhibition induced stem-like cells. Not only was there a significant decrease in mammospheres from reprogrammed cells, the aldefluor activity was totally blocked at a concentration that does not affect proliferation. This work demonstrates that HDAC inhibition mediated cancer cell dedifferentiation promotes metabolic reprogramming and highlights an FDA approved drug that targets metabolism in stem cell plasticity. Further functional endpoint studies are underway to validate these findings.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-03-05.

Abstract P5-04-06: Soluble factors from activated immune cells induce epithelial mesenchymal transition in inflammatory breast cancer cells

Rationale: Inflammatory breast cancer (IBC) is the most insidious form of locally advanced disease. Emerging evidence suggests that host factors in the microenviromement may interact with underlying IBC genetics to promote the aggressive nature of the tumor. An integral part of the metastatic process involves epithelial to mesenchymal transition (EMT) where primary breast cancer cells gain motility and stem cell features that allow distant seeding. Interestingly, the IBC consortium microarray data found no clear evidence for EMT in IBC tumor tissues. However, it is unknown if soluble factors secreted by activated immune cells mediate EMT in the IBC microenvironment that may account for the absence of EMT in studies of the tumor cells themselves. Therefore, we tested whether the conditioned media of activated immune cells were capable of inducing EMT in IBC cells.

Methods: Conditioned media (CM) were generated using healthy donor peripheral blood mononuclear cells that were activated with anti-CD3 antibody immobilized to plastic and soluble anti-CD28 antibody to activate T cells through the T-cell receptor (TCR) or left unstimulated for 48 hours. Thereafter, CM from each of the cultures was harvested and filtered. Next, 48-hour pre-seeded SUM149 IBC cells were grown in culture medium consisting of 25% CM and 75% IBC culture medium for an additional 2 days. Unconditioned media and TGF-β were used as negative and positive controls, respectively for EMT. Following treatment with CM, RNA was extracted from the target cells and analyzed for the presence of EMT-related transcription factors (EMT-TF) and markers of epithelial and mesenchymal states by TaqMan® qRT-PCR. Subsequently, a panel of 24 genes was tested on 4 IBC cell lines (SUM149, SUM190, KPL4 and IBC-3) and 5 non-IBC cell lines (MCF-10a, MCF-7, MDA-231, and MDA-453) treated with immune-activated CM using the Fluidigm® Dynamic Array integrated fluidic circuit (“chip”) gene expression platform which allows for the simultaneous quantification of 2,304 data points using TaqMan® assays. Formalin-fixed, paraffin embedded blocks were prepared from trypsinized cells for immunohistochemical (IHC) staining to detect E-cadherin and vimentin expression.

Results: SUM149 cells cultured in the presence of TCR-activated CM for two days showed upregulation in EMT-TFs (SNAIL1, ZEB1, and TG2), vimentin and fibronectin by qRT-PCR. IHC staining showed increases in both vimentin and E-cadherin expression after 48-hour exposure to anti-TCR CM. Fluidigm® gene expression analysis of multiple cell lines exposed to anti-TCR CM showed that E-cadherin expression was unchanged or slightly decreased in non-IBC cell lines, whereas 3 of 4 IBC cell lines showed an increase in E-cadherin.

Discussion: These data suggest that soluble factors secreted by activated immune cells are capable of inducing EMT in IBC cells and may mediate the persistent E-cadherin expression observed in IBC. Such processes may contribute to the highly aggressive nature of the disease; however, an immune competent in vivo model is warranted to fully understand the implications of these findings.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-04-06.

Abstract P3-10-05: Response to neoadjuvant systemic therapy (NST) in inflammatory breast cancer (IBC) according to estrogen receptor (ER) and HER2 expression

Background: Inflammatory breast cancer (IBC) is the most aggressive form breast cancer. NST, followed by local therapy (surgery and radiation therapy), is considered the current standard therapy for IBC. Among noninflammatory breast cancers, sensitivity to NST differs based on ER and HER2 status. However, whether the sensitivity to NST also differs in primary IBC based on ER status or other prognostic factors has not been studied in a large cohort.

Methods: We retrospectively reviewed 1078 patients (pts) newly diagnosed with IBC from April 1989 to January 2011. Of these, 838 pts met our inclusion criterion of stage III disease at diagnosis, and 713 of these pts had received NST and surgery. Among this population, 545 pts had information available on both ER and HER2 status. We compared pathological complete response (pCR) rates (defined as no evidence of invasive disease in the breast and ipsilateral axillary limph nodes) and clinical characteristics between ER and HER2-status subgroups and analyzed their clinical outcome. We used the Kaplan-Meier method to estimate the median recurrence-free survival (RFS) after surgery and overall survival (OS), and the Cox proportional hazards regression model to test the statistical significance of potential prognostic factors in each group.

Results: Overall 177 pts had ER+HER2− tumors; 75, ER+HER2+; 134, ER-HER2+; and 159, ER-HER2−. NST consisted of anthracycline-based [A] alone, a taxane [T] alone or with A+T; HER2 targeting therapies (H) were administered to 117 patients with HER2-positive breast cancer after 1998. Overall pCR rate was 14.7%. pCR rates are shown by marker subtype and NST received in the table below. pCR rate, nuclear grade, vascular invasion, clinical response to NST, adjuvant treatment, radiation therapy, and adjuvant hormonal therapy differed significantly among subgroups.

The median RFS and OS for all patients was 19.2 and 33.2 months, respectively. In multivariate analysis, BMI, ER status, lymphatic invasion, radiation therapy, and pCR rate were associated with RFS, and ER status, vascular invasion, radiation therapy, and pCR rate were associated with OS. Except in the ER+HER2− group, pCR was associated with better prognosis compared to non-pCR. Adjuvant hormonal therapy improved RFS both in ER+HER2+ and ER+HER2− groups, but did not improve OS in the ER+HER2+ group. Among 209 patients with HER2+ IBC, 134 received HER2 targeting therapies in neoadjuvant or adjuvant chemotherapy, and had a trend to improvement in RFS compared to chemotherapy alone (p = 0.082). The ER-HER2− group showed poorest outcome compared to other subgroups (P &lt; 0.001).

Conclusions: Sensitivity to NST differs depending on the ER and HER2 status in IBC pts. pCR rates based on these subgroups appear to be low. There is a need more effective treatments in the neoadjuvant and adjuvant therapies for all subgroups of IBC.

Abstract P5-03-10: HIF-1alpha knockout radiosensitizes select Inflammatory Breast Cancer cells through reduction of stem-like cancer cells

Independent of the tumor stroma, HIF-1α regulates tumor cell metabolism, cell proliferation and DNA repair pathways, which may produce conflicting responses to radiation, promoting either radioresistance or radiosensitization. Recently, HIF-1α was shown to increase tumor initiating cells (TICs) activity in normoxic tumor cells derived from the MMTV-PyMT trasngenic mouse model of luminal-like breast cancer. While TICs have been reported to be relatively radio-resistant, the role of HIF-1α in mediating the radation response in breast cancer TICs remains unknown. Herein, we examined radiosenstitivity of TICs derived from either PyMT HIF-1α knock out (KO) tumor cells or human breast cancer cell lines transduced with a HIF-1α dominant negative (DN) construct. Consistent prior results that loss of HIF-1 activity reduces TIC frequency, down-regulation of HIF-1 activity through the HIF DN construct reduced mammosphere formation in SUM-159, SUM-149 and MCF-7 cells (by 5.0-, 2.0-, and 2.0-fold respectively). Moreover, β-catenin expression was down-regulated in SUM-149 and SUM-159 cells transfected with the HIF-1α DN construct. Moreover, SUM-149 cells expressing the HIF-1α DN construct exhibited delayed tumor growth in vivo (p = 0.05). Standard clonogenic assays demonstrated that PyMT HIF-1α KO cells and SUM-149 cells expressing the HIF-1α DN construct were more sensitive to radiation therapy (SF6 of PyMT, HIF-1α:Control, 0.016:0.087), but that the PyMT KO and SUM-149 mammospheres that persisted after radiation were completely radioresistant (SF6 of PyMT, HIF-1 α: Control, 0.48:0.44). In contrast, MCF-7 cells were not radiosensitized in either standard or mammosphere assays. Interestingly, in HIF-1α DN MCF-7 cells, molecular features of IBC were observed, such as the increased expression of E-Cadherin and loss of Wisp3. But, Notch1 protein expression was unchanged between HIF-1α DN MCF7 or SUM149 cells. Moreover, concurrent radiation in the presence of a gamma secretase inhibitor or with a p53-MDM2 inhibitor nutlin failed to radiosensitize HIF KO mammosphere clonogens. We conclude that downregulation of HIF-1 activity selectively radiosensitizes IBC clonogenic cells but fails to radiosensitize the residual mammospheres. These data suggest that the known HIF-1α mediated mechanisms that favor radiosensitivity, such as the promotion of glycolysis and proliferation under stress, may predominate in mammospheres, which ultimately leads to radioresistance in residual mammospheres after HIF inhibition.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-03-10.

Abstract P2-03-01: Identification of cancer stem cells (CD44+CD24−/lo) in bone marrow as a prognostic factor in early breast cancer patients

Background: Cancer stem cells (CSCs) in bone marrow (BM) are epithelial tumor cells that express CD44+CD24−/lo. CSCs can be further divided into those that have ALDH activity (Aldefluor+) and those that do not. We hypothesized that if CSCs are responsible for tumor dissemination, their presence in BM would be prognostic in early stages of breast cancer (EBC) patients. Therefore, using multiparameter flow cytometry (FACS), we assessed epithelial cells for expression of CD44+CD24−/low and Aldefluor in BM of EBC patients and correlated these findings with circulating tumor cells (CTC), disseminated tumor cells (DTC) and clinical outcome.

Methods: This is a prospective laboratory study (Protocol 04–0657) conducted in the Departments of Surgical Oncology and Hematopathology, at The University of Texas MD Anderson Cancer Center in Houston, TX, USA, and was approved by the institutional review board. BM aspirates were collected at the time of surgery from 108 patients with EBC. BM was analyzed for CSCs and ALDH activity by FACS analysis. Ten cytospin slides of the bone marrow mononuclear cells were prepared from each BM aspirate and reacted with a cocktail of antibodies, including AE1/AE3, CAM5.2, MNF116, CK8 and CK18, to identify epithelial cells (DTC) by immunohistochemistry (IHC). In addition, the CellSearch system (Veridex, Raritan, NJ) was used to enumerate CTCs in each of 3 tubes of 7.5 mL of peripheral blood per patient. Overall survival (OS) and disease-free survival (DFS) were calculated from the date of diagnosis and analyzed with Kaplan-Meier survival plots. Cox multivariate proportional hazards model was also performed.

Results: Of the 103 evaluable patients, 45 patients received neoadjuvant chemotherapy, 35 adjuvant chemotherapy and 23 no chemotherapy. The median follow-up was 40 months (range 7–66 months). Patients with CSCs in BM had a hazard ratio (HR) of 8.8 for DFS (p = 0.002); patients with Aldefluor+ CSCs had a HR of 5.9 (p = 0.052) for DFS. Seven patients have expired and all of them had CSCs in BM. Moreover, we evaluated the presence of DTCs by FACS (CD326+CD45−) in 104 patients. Sixty-one (75%) of patients had positive BM samples for DTC (CD326+CD45- BM cells ≥ 0.53%). No association was shown between DTC in BM as determined by FACS and CTCs in PB. In a multivariate model, after adjusting for age (&lt; 45 years old), clinical T stage, N stage, ER, PR, HER2 status, and nuclear grading, the presence of CSCs was found to be an independent predictor of DFS (HR = 15.8, P = 0.017) as was the presence of CTCs (HR = 13.9, P = 0.007). In this subset of patients, the presence of Aldefluor+ CSCs and DTCs was not found to be predictive of DFS in the multivariate model including the same factors as listed above.

Conclusions: Our data indicate that the presence of BM metastasis is correlated to CSCs, and CSCs irrespective of ALDH activity are independent adverse prognostic factors in EBC patients. Moreover, the presence of CTCs was a strong independent predictor of DFS.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-03-01.

The value of ultrasound in detecting extra-axillary regional node involvement in patients with advanced breast cancer

Assessment of the regional lymphatics is important for accurate staging and treatment of breast cancer patients. We sought to determine the role of regional ultrasound in providing clinically relevant information. We retrospectively analyzed data from patients who were treated curatively in 1996-2006 at The University of Texas MD Anderson Cancer Center for clinical stage III breast cancer. We compared differences in regional lymph node staging based on ultrasound versus mammography and physical examination in the 865 of 1,200 patients who had external-beam radiation as part of their treatment and regional ultrasound studies as part of their initial evaluation. Ultrasound uniquely identified additional lymph node involvement beyond the level I or II axilla in 37% of the patients (325 of 865), leading to a change in clinical nodal stage. Ninety-one percent of these abnormalities that could be biopsied (266 or 293) were confirmed to contain disease. The sites of additional regional nodal disease were: infraclavicular disease, 32% (275 of 865); supraclavicular disease, 16% (140 of 865); and internal mammary disease, 11% (98 of 865). All patients with involvement in the extra-axillary regional nodal basins received a radiation boost to the involved areas ≥ 10 Gy. Thus, over one third of patients with advanced breast cancer had their radiation plan altered by the ultrasound findings. Regional ultrasound evaluation in patients with advanced breast cancer commonly revealed abnormalities within and beyond the axilla, which changed the clinical stage of disease and the radiation treatment strategy. Therefore, regional ultrasound is beneficial in the initial staging evaluation for such patients.

Current clinical coverage of Radiation Therapy Oncology Group-defined target volumes for postmastectomy radiation therapy

PURPOSE

The Radiation Therapy Oncology Group (RTOG) has published consensus guidelines for contouring relevant anatomy for postmastectomy radiation therapy (RT). How these contours relate to current treatment practices is unknown. We analyzed the dose-volume histograms (DVHs) for these contours using current clinical practice at University of Texas MD Anderson Cancer Center and compared them with the proposed treatment plans to treat RTOG-defined targets to full dose.

METHODS AND MATERIALS

We retrospectively analyzed treatment plans for 20 consecutive women treated with postmastectomy RT for which the treatment targets were the chest wall (CW), level III axilla (Ax3), supraclavicular (SCV), and internal mammary (IM) nodes. The RTOG consensus definitions were used to contour the following anatomic structures: CW; level I, II, and III axillary nodes (Ax1, Ax2, Ax3); SCV; IM; and heart (H). DVHs for these contours and the ipsilateral lung were generated from clinically designed treatment that had actually been delivered to each patient. For comparison regarding dose to normal tissue, new treatment plans were generated with the goal of covering 95% of the anatomic contours to 45 Gy.

RESULTS

The prescribed dose was 50 Gy in each case. The mean percent of volumes that received 45 Gy (V45) for the RTOG guideline-based contours were CW 74%, Ax1 84%, Ax2 88%, Ax3 96%, SCV 84%, and IM 80%. Mean heart V10 values were 11% for treatment of left-sided tumors and 6% for right-sided tumors. Mean ipsilateral lung V20 values were 28% for left-sided tumors and 34% for right-sided tumors. For the contour-based plans, mean V45 values were CW 94%, Ax1 95%, Ax2 97%, Ax3 98%, SCV 98%, and IM 85%. Mean heart V10 values were 14% for treatment of left-sided tumors and 12% for right-sided tumors. Mean ipsilateral lung V20 values were 32% for left-sided tumors and 45% for right-sided tumors.

CONCLUSIONS

Clinically derived treatment plans, which have proven efficacy and are the current standard, cover 74% to 96% of the anatomy-based RTOG consensus volumes to the prescription dose. This discrepancy should be considered if treatment planning protocol guidelines are designed to incorporate these new definitions.

Molecular comparison of human triple-negative inflammatory breast cancer (TN-IBC) and human triple-negative noninflammatory breast cancer (TN-non-IBC)

1047

Background: IBC has a poor prognosis because of its high rate of recurrence. There is an urgent need to define the biology of IBC to develop molecular-based targeted therapies for this disease. TNBC has a similar poor prognosis. Recently, Lehmann et al. (JCI, 2011) identified 7 subtypes of TNBC: basal-like (BL) 1 and 2, immunomodulatory (IM), mesenchymal (M), mesenchymal stem-like (MSL), luminal androgen receptor (LAR), and “unknown.” In light of these findings, we hypothesized that the distribution of TNBC subtypes differs between TN-IBC and TN-non-IBC. Methods: We qualitatively reproduced the Lehmann et al. experiments using Affymetrix CEL files from the same datasets to ensure the reproducibility of their findings. We quantified all arrays using frozen robust multiarray analysis with a linear model adjustment to account for batches. Then validated the results in a TNBC cohort from the World IBC Consortium for which IBC status was known (41 cases of TN-IBC; 53 cases of TN-non-IBC). We used the Fisher exact test to determine associations between TNBC subtypes and IBC status. We used Kaplan-Meier curves and log-rank tests to compare clinical outcomes between TNBC subtypes. Results: We found the 7 subtypes for both TN-IBC and TN-non-IBC. While the correspondence between our findings and those of Lehmann et al. was not perfect, there was a very significant correlation (P<2.2x10-16). We found no association between TNBC subtype and IBC status (P=.5023). As expected, we found that patients with IBC had significantly worse recurrence-free survival (RFS) than a comparison cohort of patients with advanced non-IBC that included not only patients with TNBC but also patients with ER-positive and HER2-amplified tumors (P=.0054). However, TNBC subtype did not predict RFS. IBC status was not a significant predictor of RFS or overall survival in the TNBC cohort. Conclusions: Both TN-IBC and TN-non-IBC are heterogeneous. TNBC subtypes are unrelated to IBC status. TN-IBC and TN-non-IBC have the same subtypes and clinical outcome. [Table: see text]

Limited efficacy and significant toxicities of lapatinib (Lap) plus chemotherapy as neoadjuvant therapy (NAC) for HER2-positive inflammatory breast cancer (IBC) patients (Pts)

594

Background: IBC is a rare disease but the most aggressive form of locally advanced breast cancer with a higher frequency of HER2 neu amplification (HER2+) compared to non-IBC. The EGFR pathways are also important therapeutic targets in IBC. (Zhang D, 2009). Lap is an oral reversible dual kinase inhibitor of epidermal growth factor receptor of EGFR and HER2. Our objective was to determine the efficacy of Lap in combination with paclitaxel as NAC in pts with previously untreated HER2+ IBC. The primary end-point was to determine the rate of pathological complete response (pCR) defined as no residual invasive disease in the breast and the axillary lymph nodes or Residual Cancer Burden (RCB) of 0. (Symmans FW, 2008). The second endpoint was to assess general safety and cardiac toxicity of this combination therapy. Methods: From October 2008 to May 2011, 15 chemo-naïve pts were treated with Lap 1,250 mg/day as a single agent for 2 weeks, followed by 12 weeks of paclitaxel (80 mg/m2 weekly) plus Lap (1,000 mg/day), and finally with 4 cycles of FEC-75 mg/m2 regimen plus Lap (1,000 mg/day) before surgery. Among 12 first pts enrolled, 6 pts had grade 3 diarrhea (CTCAC v3.0) and the protocol was amended to reduce the Lap dose to 750 mg/day. After modified radical mastectomy (MRM), patients received radiation therapy and one year of adjuvant trastuzumab. Results: Median age was 53.8 (range, 39 -70), performance status was 0 (13 pts), 1 (2 pts), 4 pts had metastatic disease at diagnosis. 10 of 15 pts had MRM. One pt achieved pCR. Five pts did not complete the NAC due to grade 2 cardiomyopathy (1), liver dysfunction (2), diarrhea (1), and insurance denial after pt started treatment (1). The trial was stopped early due to severe toxicity (>15%) and lack of efficacy. Conclusions: Lap in combination with chemotherapy as NAC has a limited anti-tumor activity in pts with HER2+ IBC with a pCR rate of 6.6%. Lap and paclitaxel was associated with severe diarrhea toxicity and required multiple dose reductions of Lap. With the recent promising results in HER2+ NAC studies, the role of Lap should continue to be explored in combination with other anti-HER2 agents in IBC patients.

Primary tumor resection to improve survival and local disease control in stage IV inflammatory breast cancer

1102

Background: Inflammatory breast cancer (IBC) is a rare and aggressive form of breast cancer typically presenting with early metastasis. Optimal outcomes are achieved with multimodality treatment strategies in the non-metastatic setting. Data is limited, however, on the benefit of surgery in patients with metastatic IBC. We evaluated the effect of primary tumor resection on outcomes in patients with newly diagnosed stage IV IBC. Methods: We reviewed records of 172 patients with metastatic IBC treated at our institution from 1994 - 2009. All patients received systemic therapy with or without locoregional therapy (LRT). Patient demographics, receptor (ER) and HER2-neu status, grade, histology, presence of lymphovascular invasion, margin status, number of distant disease sites, pathologic response of primary tumor and clinical response to systemic therapy (CRS) at distant disease sites were recorded. Overall survival (OS), distant progression-free survival (DPFS), and chest/skin involvement at last follow-up were evaluated. Kaplan-Meier survival analyses, univariate (UV) and multivariate (MV) logistic regression models were used. Chest/skin involvement was compared between groups using Kruskal-Wallis test. Results: Seventy-nine (45%) patients underwent primary tumor resection. Average age was 51 (22-78). Median live-patient follow-up was 33 months. OS and DPFS were significantly better for patients who underwent LRT versus none (p<0.0001). Factors associated significantly for improved DPFS on MV analysis were ER and HER2-neu status (HR 0.61,0.60 p=0.02,0.05 ,respectively), LRT (HR .38, p=0.002) and CRS (HR 0.62, p=0.03). ER status (HR .45, p<0.001), LRT (HR .30, p<0.001) and CRS (HR 0.54, p=0.02) were significant predictors for higher OS on MV analysis. At last follow up, chest/skin involvement was moderate/severe in 11% of patients in LRT group versus 35% of patients in no LRT group (p<0.0001). Conclusions: This latest retrospective study demonstrates metastatic IBC patients who undergo LRT in addition to systemic therapy may have improved survival and local control outcomes. CRS may be used to guide LRT. A prospective randomized trial is needed to validate these findings.

Field match verification during combination proton, photon, and electron therapy for oligometastatic inflammatory breast cancer

Postmastectomy radiation therapy (PMRT) has been shown in randomized trials to improve overall survival for patients with locally advanced breast cancer. The standard PMRT clinical target volume (CTV) encompasses the chest wall and undissected regional lymphatics. Conformal isodose distributions covering the standard CTV with acceptable dose limits to normal tissue can typically be achieved with a combination of photon and electron fields. Field borders are marked on the patient's skin using a light field projection of each beam and are subsequently used to verify daily field matching clinically. Initial imaging of a patient with oligometastatic inflammatory breast cancer demonstrated direct extension of disease from the involved internal mammary lymph node chain into the anterior mediastinum as the only site of metastatic disease. The patient achieved a pathologic complete response to neoadjuvant chemotherapy and underwent mastectomy. The initial sites of gross disease, including the anterior mediastinal node was included in the CTV for PMRT, and treatment planning demonstrated a clear advantage to the inclusion of proton fields in this case. The absence of a light source on the proton delivery system that accurately projects proton field edges onto the patient's skin posed a significant challenge for daily verification of proton-to-photon and -electron field matching. Proton field-specific radiographic imaging devices were designed and used such that proton field edges could be delineated on the patient's skin and used for daily matching with photon and electron fields. Manufacture of the imaging devices was quick and inexpensive. Weekly verification of proton field alignment with the proton field delineation on the skin demonstrated agreement within 3-mm tolerance. The patient remains with no evidence of disease 18 months after completing radiation. Other patients with similar indications may benefit from multimodality radiation therapy.

Inflammatory breast cancer: what we know and what we need to learn

PURPOSE

We review the current status of multidisciplinary care for patients with inflammatory breast cancer (IBC) and discuss what further research is needed to advance the care of patients with this disease.

DESIGN

We performed a comprehensive review of the English-language literature on IBC through computerized literature searches.

RESULTS

Significant advances in imaging, including digital mammography, high-resolution ultrasonography with Doppler capabilities, magnetic resonance imaging, and positron emission tomography-computed tomography, have improved the diagnosis and staging of IBC. There are currently no established molecular criteria for distinguishing IBC from noninflammatory breast cancer. Such criteria would be helpful for the diagnosis and development of novel targeted therapies. Combinations of neoadjuvant systemic chemotherapy, surgery, and radiation therapy have led to an improved prognosis; however, the overall 5-year survival rate for patients with IBC remains very low (∼30%). Sentinel lymph node biopsy and skin-sparing mastectomy are not recommended for patients with IBC.

CONCLUSION

Optimal management of IBC requires close coordination among medical, surgical, and radiation oncologists, as well as radiologists and pathologists. There is a need to identify molecular changes that define the pathogenesis of IBC to enable eradication of IBC with the use of IBC-specific targeted therapies.

Hormone receptor status influences the locoregional benefit of trastuzumab in patients with nonmetastatic breast cancer

BACKGROUND

Previous studies have shown that hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status influence the outcome of locoregional treatments. However, the interrelationship of these factors with trastuzumab is unclear. In this study, the role of HR and HER2 status on the locoregional benefit of trastuzumab treatment was investigated in patients with nonmetastatic breast cancer.

METHODS

Locoregional outcomes of 5683 women treated at The University of Texas MD Anderson Cancer Center from 2000 to 2008 for invasive breast cancer were analyzed using Kaplan-Meier and Cox regression methods to compare 6 subgroups: HR-positive (HR+)/HER2-negative (HER2-), HR-/HER2- (triple-negative), HR+/HER2+ with or without trastuzumab, and HR-/HER2+ with or without trastuzumab.

RESULTS

Overall, locoregional recurrence (LRR) was 5% at 5 years among patients with HER2+ disease. Patients with HR+/HER2+ disease treated with trastuzumab had half the rate of LRR as patients who did not receive trastuzumab, whereas patients with HR-/HER2+ disease had similar rates of LRR regardless of trastuzumab treatment. On Cox regression analysis comparing LRR risk to the cohort with HR+/HER2- disease, only the HR+/HER2+ cohort treated with trastuzumab had similar LRR risk (hazard ratio = 1.24, 95% confidence interval = 0.56-2.73, P = .591). All other subgroups, including the HR+/HER2+ cohort who did not receive trastuzumab, had significantly worse outcomes. LRR risk was highest among patients with triple-negative disease (hazard ratio = 4.73, 95% confidence interval = 3.42-6.54, P < .001).

CONCLUSIONS

Among patients with HR+/HER2+ disease, treatment with trastuzumab reduces LRR risk to the more favorable outcome of patients with HR+/HER2- disease. In contrast, the increased LRR risk among patients with HR-/HER2+ disease remains despite treatment with trastuzumab. Additional locoregional strategies are needed in this subgroup of patients.

Abstract 5210: Impact of tumor microenvironment on expansion of tumor initiating cells in breast cancer metastasis

Breast cancer metastasis which ultimately results in breast cancer death, is an event believed to be initiated by the migration of tumor initiating cells (TIC) from the primary tumor to niches for micrometastatic disease. Recent data suggests the tumor microenvironment promotes TIC. The clinical relevance of secreted factors from the microenvironment on TIC surrogate, mammosphere (MS) formation and MS sensitivity to drug therapy was investigated using breast cancer patient fluids inherently conditioned by the tumor microenvironment: post-operative seromas and malignant pleural effusions. Fluids from 20 patients with breast cancer (8 seromas and 13 pleural effusions) and mesenchymal stem cells (MSC) from healthy donors were collected on IRB approved protocols. Cellular components were eliminated from patient-derived fluids using density-gradient centrifugation. MSC conditioned media (MSC-CM) was collected from 3D cultures of primary MSC. Luminex multiplex array platform was used to characterize 79 cytokine and growth factor components of all fluids. In addition, MSC-CM and patient-derived fluids were added to cultures of breast cancer cell lines: MCF-7, an estrogen receptor (ER)-positive cell line; SUM149, a triple-negative inflammatory breast cancer cell line; and SUM159, a triple-negative metaplastic breast cancer cell line and MS forming efficiency was examined. Our results show that pleural effusions and seromas are enriched for factors also secreted by MSC such as MCP-1, GRO, IL-6 and IL-8. We found remarkable similarities regarding the cytokines and growth factors profile in pleural effusions and seromas. Both patient-derived fluids have comparable amount of IL-2, IL-3, IL-4 and IL-10, as well as, VEGF, EGF and FGF-b. IL-1β and IL-16 were significantly different between pleural effusions and seromas. Seroma fluid from bilateral drains in a patient with an invasive cancer and a contralateral benign mastectomy had very similar cytokine concentrations. Moreover, MSC-CM and pleural fluids from ER+ and ER- patients increased the MS formation efficiency of both triple-negative cell lines while seroma fluids from ER+ and ER- patients increased the MS formation efficiency of ER-positive cell line MCF-7. Finally, we evaluated the impact of a panel of drugs on cell cultures grown with MSC-CM and patient-derived fluids. We found that the effect of chemotherapies on MS formation can be attenuated by patient-derived fluids. Seroma and pleural effusion fluids from breast cancer patients have similar cytokine profiles, change MS formation efficiency of standard breast cancer cell models, and mediate sensitivity to therapy. Here we demonstrate that host and microenvironmental factors are critical for determining resistance to therapy. Future studies will investigate the prognostic implications of factors that promote TIC survival in the fluid tumor microenvironment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5210. doi:1538-7445.AM2012-5210

Abstract 5044: Radiation modulates expression of microRNAs in breast cancer cell lines grown under adherent and stem cell promoting culture conditions

Although mounting evidence demonstrates that cancer stem/progenitor cells are radioresistant, explicit mechanisms of resistance have not been fully explored. MicroRNAs (miRNAs) are small noncoding RNAs that are involved in regulating cancer stem cell self-renewal and play an important role in response to cellular stress. Few studies have been conducted to investigate the role of specific miRNAs in cellular radiation response. Knowledge of how radiation therapy modulates miRNA expression in cancer stem cells vs. non-stem cells is critical to developing cancer stem cell sensitizers. We isolated total RNA from adherent (2D) and non-adherent mammosphere (3D) cultures of six breast cancer cell lines (MCF12F, MCF7, SUM190, SUM149, MDA-IBC-3, and SUM159) subjected to 0Gy or 4Gy radiation and examined differentially expressed miRNAs using Exiqon's miRCURY microarray. Analysis of the data showed 62 differentially expressed miRNAs between 2D and 3D independent of radiation treatment (fold change of at least 1.5, FDR &lt;0.1; P&lt;0.05). While no radiation based signature was observed when comparing all irradiated samples to unirradiated samples, assessment of each cell line indicated that the levels of specific microRNAs were altered in response to radiation treatment in 2D and 3D cells. Further studies to validate the functions of top candidate miRNAs using inhibitors or mimics to alter the self renewal and radiosensitivity of cancer stem cells are underway.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5044. doi:1538-7445.AM2012-5044

P1-04-03: The Effect of Survivin Downregulation on Radiosensitization of Breast Cancer Cell Lines Grown under Adherent and Stem Cell Promoting Culture Conditions

Survivin, the smallest member of the inhibitor of apoptosis protein (IAP) family, is a bifunctional protein that has been implicated in both control of cell division and inhibition of apoptosis. Survivin has been shown to be involved in radiation resistance of various cancer types and its expression is increased by sublethal doses of irradiation in both differentiated and cancer stem cell (CSC) population. However, it is unknown whether suppression of survivin radiosensitizes the CSC population or diminishes its self renewal ability. Herein, we cloned the survivin dominant-negative mutant lacking a phosphorylation site (T34A) (Mesri et al., 2001 JCI) into the lentiviral LeGo vectors and assessed mammosphere formation and radiosensitization in MCF7, SUM149 and SUM159 cell lines grown under adherent or stem cell promoting conditions. We found an induction of survivin by western blotting in the dominant negative mutant (T34A)-transfected cell lines. Moreover, we observed a higher than two-fold increase in the Sub-G1 population as well as an increased Caspase 3 activity in the T34A-transfected SUM149 and SUM159 cells compared to control cells indicating an anti-apoptotic function of survivin. We also found that T34A-transfected cells showed a 1.5 to 2-fold decrease in the number of mammospheres compared to the control-transfected cells. Furthermore, T34A-transfected cells showed radiosensitization in adherent cells from SUM149 and SUM159 cells but no effect was observed in MCF7 cells. However, no radiosensitization was observed in stem cell promoting culture conditions with increasing doses of radiation in all tested cell lines. This indicates that the widely used standard clonogenic assays do not optimally select anti-CSC agents and that targeted therapies should be specifically tested for their activity against the CSC population. Further functional endpoint studies will be conducted to validate the in vitro findings.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-04-03.