High-density and very-low-density lipoprotein have opposing roles in regulating tumor-initiating cells and sensitivity to radiation in inflammatory breast cancer

PURPOSE

We previously demonstrated that cholesterol-lowering agents regulate radiation sensitivity of inflammatory breast cancer (IBC) cell lines in vitro and are associated with less radiation resistance among IBC patients who undergo postmastectomy radiation. We hypothesized that decreasing IBC cellular cholesterol induced by treatment with lipoproteins would increase radiation sensitivity. Here, we examined the impact of specific transporters of cholesterol (ie lipoproteins) on the responses of IBC cells to self-renewal and to radiation in vitro and on clinical outcomes in IBC patients.

METHODS AND MATERIALS

Two patient-derived IBC cell lines, SUM 149 and KPL4, were incubated with low-density lipoproteins (LDL), very-low-density lipoproteins (VLDL), or high-density lipoproteins (HDL) for 24 hours prior to irradiation (0-6 Gy) and mammosphere formation assay. Cholesterol panels were examined in a cohort of patients with primary IBC diagnosed between 1995 and 2011 at MD Anderson Cancer Center. Lipoprotein levels were then correlated to patient outcome, using the log rank statistical model, and examined in multivariate analysis using Cox regression.

RESULTS

VLDL increased and HDL decreased mammosphere formation compared to untreated SUM 149 and KPL4 cells. Survival curves showed enhancement of survival in both of the IBC cell lines when pretreated with VLDL and, conversely, radiation sensitization in all cell lines when pretreated with HDL. In IBC patients, higher VLDL values (>30 mg/dL) predicted a lower 5-year overall survival rate than normal values (hazard ratio [HR] = 1.9 [95% confidence interval [CI]: 1.05-3.45], P=.035). Lower-than-normal patient HDL values (<60 mg/dL) predicted a lower 5-year overall survival rate than values higher than 60 mg/dL (HR = 3.21 [95% CI: 1.25-8.27], P=.015).

CONCLUSIONS

This study discovered a relationship among the plasma levels of lipoproteins, overall patient response, and radiation resistance in IBC patients and IBC patient-derived cell lines. A more expansive study is needed to verify these observations.

Overall survival differences between patients with inflammatory and noninflammatory breast cancer presenting with distant metastasis at diagnosis

Inflammatory breast cancer (IBC) is a rare and aggressive disease. Previous studies have shown that among patients with stage III breast cancer, IBC is associated with a worse prognosis than noninflammatory breast cancer (non-IBC). Whether this difference holds true among patients with stage IV breast cancer has not been studied. We tested the hypothesis that overall survival (OS) is worse in patients with IBC than in those with non-IBC among patients with distant metastasis at diagnosis (stage IV disease). We reviewed the records of 1504 consecutive patients with stage IV breast cancer (IBC: 206; non-IBC: 1298) treated at our institution from 1987 through 2012. Survival curves for IBC and non-IBC subcohorts were compared. The Cox proportional hazards model was used to determine predictors of OS. The median follow-up period was 4.7 years. IBC was associated with shorter median OS time than non-IBC (2.27 vs. 3.40 years; P = 0.0128, log-rank test). In a multicovariate Cox model that included 1389 patients, the diagnosis of IBC was a significant independent predictor of worse OS (hazard ratio = 1.431, P = 0.0011). Other significant predictors of worse OS included Black (vs. White) ethnicity, younger age at diagnosis, negative HER2 status, and visceral (vs. nonvisceral) site of metastasis. IBC is associated with shorter OS than non-IBC in patients with distant metastasis at diagnosis. The prognostic impact of IBC should be taken into consideration among patients with stage IV breast cancer.

Abstract P3-08-01: Gamma-ray induced mutagen sensitivity and overall survival in young women with breast cancer

Background:

Hypersensitivity to radiation has been shown to be a risk factor for the development of breast cancer. We aim to determine whether the same hypersensitivity predicts for adverse clinical outcomes in patients diagnosed with carcinoma of the breast.

Methods:

465 young, female, non-Hispanic white patients diagnosed with carcinoma of the breast at our institution from 1/1997 to 12/2005 were included in this study. All cases were histologically confirmed and all blood was drawn prior to any systemic or local therapy. Patient age, body mass index (BMI), menopause status, tumor laterality, AJCC stage, ER status, nuclear grade, and receipt of chemotherapy and radiation were extracted from patient medical records. A gamma-ray-induced mutagen sensitivity assay was performed using standard published methods to evaluate individual responses to radiation. The number of simple chromatid breaks per sample was counted from 50 well-spread metaphases. Each simple chromatid break was counted as a single break and each isochromatid break, exchange figure, or interstitial deletion as two breaks. The mean value of chromatid breaks per cell (b/c) was then calculated and recorded. Cox multivariable proportional hazards model was used to estimate the hazard ratio (HR) and 95% confidence interval (CI) for the association between b/c and overall survival.

Results:

A total of 402 patients had a b/c value recorded and were included in the final analysis. The patient median age was 46 years (range 22-55). 341 patients (84.8%) had invasive cancer and 253 patients (69.9%) had ER+ disease. AJCC stage distribution was stage 0 (15.2%), stage 1 (41.5%), stage 2 (33.5%), stage 3 (9.5%) and stage 4 (0.3%). The median follow-up for all patients was 97.2 months (interquartile range, IQR 83.3-119.6 months). The median b/c was 0.5 (IQR 0.38-0.62). The 5 and 10-year survival for all patients was 92.6% and 87.5%. A statistically significant decrease in 5 and 10-year overall survival was seen in patients with b/c greater than the median value of 0.5 (96.2% vs. 89.2%, p=.007 and 90.8% vs. 84.5%, p=.046, respectively). On multivariable analysis (MVA), age at diagnosis (HR 0.95, CI 0.91-0.99, p=.017), BMI (HR 1.07, CI 1.03-1.12, p=.003), ER status (HR= 0.31, CI 0.16-0.61, p=.01), AJCC stage (HR 1.91, CI 1.2-3.0, p=.006), and b/c level (HR 5.67, CI 1.5-18.2, p=.01) all predicted for overall survival. Excluding the 61 patients with in situ disease, there remains a significant difference in survival at both 5 and 7 years (95.5% vs. 88.5%, p=.017 and 93.5% vs. 86%, p=.021). A trend for decrease survival was seen at 10 years (p=0.09). On MVA for patients with invasive disease, age at diagnosis (HR=0.95, 95% CI 0.91-0.99, p=.026), BMI (HR=1.06, 95% CI 1.01-1.11, p=.023), AJCC stage (HR=2.41, CI 1.51-3.91, p=.0003), and ER status (HR=0.25, CI 0.12-0.49, p&lt; .0001) and b/c level (HR=3.76, CI 1.39-8.06, p=.012) were associated with overall survival.

Conclusions:

In this cohort of young, female, non-Hispanic white breast cancer patients, a greater b/c level predicted for decreased overall survival. The use of a gamma-ray-induced mutagen sensitivity assay may be prognostic and help select for those at increased risk of death.

Citation Format: Michael C Stauder, Simona F Shaitelman, Pamela K Allen, Abenaa M Brewster, Banu K Arun, Wendy A Woodward, Thomas A Buchholz, Li-E Wang. Gamma-ray induced mutagen sensitivity and overall survival in young women with breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-08-01.

Abstract P1-15-03: Long term outcomes in patients with phyllodes tumor of the breast: The UT MD Anderson experience

Purpose: Phyllodes tumor is a relatively rare disease of the breast, and the risk factors for local versus distant failure are unclear. The goal of this study was to identify factors influencing local, distant, and cause-specific survival outcomes in patients with phyllodes tumors, and to assess the impact of local radiotherapy (RT).

Methods: We retrospectively reviewed the records of 387 patients recorded in the MD Anderson tumor registry as having "cystosarcoma phyllodes" or "phyllodes". After excluding patients with recurrent disease at presentation to the institution, concurrent invasive ductal carcinoma, absence of confirmation of phyllodes tumor, or inadequate follow up after surgery, 229 patients diagnosed from 1964-2011 were evaluable. The median tumor size was 4 cm (range, 0.7-28 cm); histology was benign in 29%, indeterminate in 7%, and malignant in 41% (23% unknown). Stromal overgrowth was present in 18% (n=40). Local therapy consisted of breast-conserving surgery (n=184) or mastectomy (n=43); 15% (n=34) also received local RT. Chemotherapy was administered in 9% (n=21). We used Kaplan-Meier analyses and Cox proportional hazards models to estimate the associations between patient/tumor characteristics and treatment on local control (LC), distant metastasis-free survival (DMFS), and cause specific survival (CSS).

Results: At a median follow-up of 76 months (range, 1-485 months), the actuarial 5-yr LC for the entire cohort was 75%; 5-yr DMFS was 78%; and 5-yr CSS was 86%. Factors influencing LC included receipt of RT (5-yr LC 97% versus 72%, p=.005) and age over 50 (85% versus 72%, p=.044). Neither malignant histology nor stromal overgrowth increased the risk of local failure. Factors influencing DMFS included malignant histology (5-yr DMFS 65% versus 91%, p=.001) and stromal overgrowth (50% versus 84%, p&lt;.001). Factors influencing CSS included malignant histology (5-yr CSS 77% versus 100%, p=.002) and stromal overgrowth (58% versus 92%, p&lt;.001). Patients with stromal overgrowth or malignant histology were much more likely to receive RT (p&lt;.001 for both factors). RT improved 5-yr LC for both breast conserved and mastectomy patients, but did not improve DMFS or CSS. In multivariable models, the following associations were noted (HR=hazard ratio; CI= 95% confidence interval): LC – RT (HR 0.13, CI .03-.55); DMFS – malignant histology (HR 2.99, CI 1.41-6.34); CSS – malignant histology (HR 4.18, CI 1.43-12.24).

Conclusions: Adjuvant RT after surgery improves local control in phyllodes tumor; however, it does not improve DMFS or CSS. Stromal overgrowth and malignant histology are associated with worse DMFS and CSS, but do not impact local control. Therefore malignant histology and stromal overgrowth should not be deciding factors in the use of local RT, as escalated local therapy in patients with these tumor characteristics does not improve DMFS or CSS. Other strategies should be considered for patients with phyllodes tumor who are at high risk of distant failure, including systemic therapy.

Citation Format: Bobbi A Porche, Pamela K Allen, Simona Shaitelman, B Ashleigh Guadagnolo, Wendy A Woodward, Constance Albarracin, Abenaa M Brewster, Kelly K Hunt, Welela Tereffe. Long term outcomes in patients with phyllodes tumor of the breast: The UT MD Anderson experience [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-15-03.

Abstract P4-04-09: Mesenchymal stem cells and macrophage interactions promote inflammatory breast cancer cell invasion and self renewal

Background: Inflammatory breast cancer (IBC) is responsible for 10% of breast cancer deaths. The hallmarks of IBC are skin involvement and a high propensity to metastasize. Our lab has shown previously, "normal" breast tissue from women with an IBC diagnosis had significantly greater macrophage infiltration and increased cells with stem cell markers compared to non IBC "normal" breast tissue. These changes were present prior to diagnosis in two patients where pre-IBC biopsies were available. Therefore, we hypothesized changes in the normal breast microenvironment prior to tumor formation contributes to the IBC phenotype.

Methods: To study our hypothesis we used a co-culture system to measure the interactions between normal macrophages (Raw 264.7 cell line), bone-marrow derived mesenchymal stem cells (MSCs), and IBC cells (SUM 149, IBC3, and KPL4). Conditioned media (CM) from MSC culture was added to macrophages overnight. The macrophages were subsequently analyzed for their surface markers and cytokine production. Reciprocally, MSCs were "educated" by macrophages by adding CM from polarized M2 macrophages to the MSC culture media at a 1:1 ratio. MSCs and cancer cells were co-cultured in trans-wells (Boyden chambers) for 24 hours. Migration and invasion in vitro was determined by adding MSCs or IBC cells to the insert of the trans-well and cultured in combination with either polarized macrophages or macrophage educated MSCs for 24 hours. After co-culture, IBC cells were analyzed for their ability to form mammospheres.

Results: Mouse macrophages polarized (using IL-4) into a M2 phenotype (Tumor associated macrophage) secreted 3 fold more IL-6 compared to unstimulated or M1 polarized macrophages. The addition of MSC CM to the macrophage culture for 24 hours polarized the macrophages into a similar M2 phenotype described above with 4-fold increase in IL-6 secretion compared to unstimulated macrophages (P&lt;0.01). When M2 macrophages at the bottom of the co-culture system were co-cultured with MSC, the number of MSCs migrating increased 2 fold with the addition of M2 macrophages compared to media alone, or unstimulated macrophages (P&lt;0.05). IBC cells showed a 2 fold enhancement of invasion towards M2 educated MSCs compared to either uneducated MSCs, or media alone (P&lt;0.05). IBC cells co cultured with M2 educated MSCs grew 3 fold more mammospheres compared to IBC cells grown with uneducated MSCs (P&lt;0.01). IBC cells added to the bottom of the co-culture system also enhanced migration of MSCs and did so to a greater extent than non-IBC cells (P&lt;0.01). Lastly, the addition of IL-6 neutralizing antibody inhibited IBC induced MSC migration.

Conclusions: Herein we demonstrate reciprocal tumor interactions between normal cells in the IBC microenvironment. MSC and macrophages can influence each other to increase the tumor promoting influence of each on IBC cells. Our results suggest IL-6 a mediator of these tumor promoting influences and is important for the IBC induced migration of MSCs. Currently we are investigating the in vivo interactions between macrophages and MSCs in an orthotopic IBC mouse model.

Citation Format: Adam R Wolfe, Rachel Atkinson, Bisrat G Debeb, Yan Zhang, Brian Ruffel, James M Reuben, Naoto T Ueno, Wendy A Woodward. Mesenchymal stem cells and macrophage interactions promote inflammatory breast cancer cell invasion and self renewal [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P4-04-09.

Abstract P6-14-07: High miR-19a serum levels correlate with favorable prognosis in patients with metastatic HER2+ inflammatory breast cancer and may result from an effective antibody-dependent cell-mediated cytotoxicity induced by trastuzumab

Background: IBC is a rare but highly aggressive form of locally advanced breast cancer (5-year OS rate: 40.5% IBC vs 85% non-IBC patients) accounting for 10% of all breast cancer deaths. To date, no unique molecular diagnostic or prognostic biomarker has been identified for IBC. Increasing evidence supports the potential value of miRNA as prognostic and predictive serum biomarker in cancer. We found that IBC cells expressed high levels of miR-19a and patients with metastatic IBC HER2+ (MIBC HER2+) and high miR-19a serum levels had better prognosis than patients with MIBC HER2+ and low miR-19a serum levels. As one of the mechanisms of action of trastuzumab is the induction of antibody-dependent cell-mediated cytotoxicity (ADCC), we hypothesized that the increased miR-19a serum levels in MIBC HER2+ patients with favorable clinical outcome could result from an effective ADCC and be used as biomarker to monitor the response to trastuzumab.

Methods: Total RNA was isolated using the Total RNA Purification Kit (Invitrogen, Norgen Biotek). MiR-19a levels in tumor tissue, serum, cell lines and supernatants were evaluated by qRT-PCR (Applied Biosystems). ADCC was evaluated by Annexin V-FITC Apoptosis Detection Kit I (BD Pharmingen).

Results: Microarray was performed in IBC (n=23) and non-IBC (n=24) tumors and normal tissue (n=12). Microarray showed higher miR-19a expression in IBC compared with non-IBC (p=0.028) and normal tissue (p=0.0002). The two IBC cell lines SUM149 (triple receptor-negative) and KPL-4 (HER2-amplified) expressed higher levels of miR-19a compared with the non-IBC cell lines MDA-231 (triple receptor-negative), SKBR3 (HER2-amplified), and MCF-7 (HER2-non-amplified) (p&lt;0.001, p&lt;0.001, p&lt;0.001 and p&lt;0.05, p&lt;0.05, p&lt;0.01 respectively). To assess whether miR-19a could be released from IBC cells upon NK cell-mediated ADCC, we performed a NK cytotoxicity test using the NK-resistant KPL-4 cells and the NK-sensitive SKBR3 and the NK-sensitive MCF-7 cells as control. Co-incubation with trastuzumab induced increased MCF-7, SKBR3 and KPL-4 cell death (2.1-fold, 2.4-fold and 3.5-fold respectively) and accordingly increased miR-19a levels in their supernatants (MCF-7: 3-fold, p=0.017; SKBR3: 6-fold, p=0.005 and KPL-4: 8-fold, p=0.0001). The pattern of miR-19a levels in the supernatants correlated with that expressed at cellular levels (MCF-7&lt;SKBR3&lt;KPL-4). We measured miR-19a serum levels in patients with MIBC HER2+ (n=27) and metastatic nonIBC HER2+ (n=24). Patients with MIBC HER2+ and high miR-19a level had longer PFS (10.3 vs 3.2 months, p=0.022) and OS (median not reached vs 11.2 months, p=0.003) than patients with low miR-19a levels. Patients with metastatic nonIBC HER2+ and high miR-19a levels had longer OS (32.9 vs 13.3 months; p=0.015) than patients with low miR-19a levels (32.9 vs 13.3 months; p=0.015).

Conclusion: High miR-19a serum levels are associated with favorable prognosis in patients with MIBC HER2+ and could result from an effective NK cell-mediated ADCC. MiR-19a may represent a novel serum biomarker to monitor the response to trastuzumab therapy and predict clinical outcome in patients with MIBC HER2+.

Citation Format: Simone Anfossi, Antonio Giordano, Lei Huo, Ricardo H Alvarez, Vicente Valero, Gabriel N Hortobagyi, Wendy A Woodward, Naoto T Ueno, George A Calin, James M Reuben. High miR-19a serum levels correlate with favorable prognosis in patients with metastatic HER2+ inflammatory breast cancer and may result from an effective antibody-dependent cell-mediated cytotoxicity induced by trastuzumab [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-14-07.

Abstract P5-07-04: Characterization of a new canine inflammatory mammary cancer (IMC) cell line (IPC-366)

Spontaneous canine inflammatory mammary cancer (IMC) shares epidemiologic, histopathological and clinical characteristics with the disease in humans and has been proposed as a natural model for human inflammatory breast cancer (IBC). Few cell lines are available to study IBC, such us SUM 149, SUM 190 and MDA-IBC3. The aim of this study was to characterize a new cell line from IMC (IPC-366) for the comparative study of both IMC and IBC. Tumors cells from a female dog with clinical IMC were collected. The pathological diagnosis of IMC was confirmed at the Veterinary Pathology Service of UCM- Veterinary Clinical Hospital. The cells were grown under adherent conditions in DMEM/F12 with 5% fetal bovine serum and 1% antibiotics (streptomycin and penicillin). The growth and mammospheres production capability, and cytological, ultrastructural and immunohistochemical (IHC) characteristics of IPC-366 were evaluated. Tumorigenicity and metastatic potential of IPC-366 were also assessed by inoculating the cells on the mammary fat pad of 18 female Balb/SCID mice and the development of tumor was monitored by imaging and luciferase assay. Microscopic examination of tumor revealed an epithelial morphology with marked anysocytosis. Doubling time of the tumor cells was approximately 24 h. Under non-adherent conditions, IPC-366 cells formed mammospheres in approximately 3 days. Cytological and histological examination of smears and ultrathin sections by electron microscopy revealed that IPC-366 is formed by highly malignant large round or polygonal cells characterized by marked atypia and prominent nucleoli and frequent multinucleated cells. Some cells had cytoplasmic empty spaces covered by cytoplasmic membrane resembling capillary endothelial cells, a phenomenon described as vasculogenic mimicry. IHC characterization of IPC-366 was basal-like: epithelial cells (AE1/AE3+, CK14+, vimentin+, actin-, p63-, ER-, PR-, HER-2 – (DAKO, HER2 P4 ), overexpressed COX-2 and high Ki-67 proliferation index (87.15 %). Imaging and luciferase assay revealed that at 3 weeks after inoculating the IPC-366 cells, a tumor mass was found in 50 % of mice. At 8 weeks after inoculation metastases in lung, liver and lymph nodes were found. Xenograph tumors maintained the original IHC characteristics of the female dog tumor. In summary, the cell line IPC-366 is a fast growing malignant triple negative cell line model of inflammatory mammary carcinoma that can be used for the comparative study of both IMC and IBC.

Citation Format: Sara Caceres, Laura Peña, Lara C Alvarez de la Cerda, Maria J Illera, Richard Larson, Hui Gao, Bisrat G Debeb, Wendy A Woodward, James M Reuben, Juan C Illera. Characterization of a new canine inflammatory mammary cancer (IMC) cell line (IPC-366) [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P5-07-04.

Abstract P6-16-01: The microRNA miR-141 is a key regulator of brain metastasis from breast cancer

Purpose: Brain metastasis poses a major treatment challenge and remains an unmet clinical need. Finding novel therapies to prevent and treat brain metastases requires an understanding of the biology and molecular basis of the process, which currently is constrained by a dearth of experimental models and specific therapeutic targets. The purpose of this study was to develop preclinical models and identify molecular mediators of brain metastasis from breast cancer.

Methods: We used MDA-MB-IBC3 (ER-/HER2+), SUM149 (ER-/HER2-), MCF7 (ER+/HER2-), SUM159 (ER-/HER2-) and MDA-MB-231 (ER-/HER2-) cell lines for this study. GFP-labeled cells were injected via tail vein into SCID/beige mice and metastatic colonization to the brain and lung evaluated by fluorescent stereomicroscope and histology 8-weeks after injection. miRNA microarray was performed with miRNA 3.0 Array. Stable knockdown of miR-141 was achieved with the lentiviral miRZip system. MiR-141 serum levels in 105 breast cancer patients were measured using quantitative PCR.

Results: We developed novel brain metastasis models in which tail-vein injection of both triple-negative and a HER2-overexpressing inflammatory breast cancer lines led to a high rate of brain metastases (67%) in SCID/Beige mice (SUM149, 6 of 9 mice; MDA-MB-IBC3, 10 of 15 mice). Sub-lines derived from lung or brain metastases in these models were morphologically and molecularly distinct. The brain metastasis-derived sublines showed epithelial morphology and overexpressed epithelial markers and miR-141 while sublines from lung metastases showed mesenchymal morphology and overexpressed mesenchymal markers. Knockdown of miR-141 significantly inhibited metastatic colonization to the brain compared to controls (miR-141 knockdown vs. control: SUM149, 0 of 8 mice vs. 6 of 9 mice, p=0.009; MDA-MB-IBC3, 2 of 14 mice vs. 10 of 15 mice, p=0.007) but it did not affect colonization to the lung. Importantly, ectopic expression of miR-141 in non-expressing MDA-MB-231 significantly enhanced brain metastatic colonization (5 of 9 mice vs. 0 of 10 mice, P=0.02). On multivariate analyses high serum level of miR-141 was an independent predictor of progression free survival [HR 4.8 (95%CI, 2.6-8.7), P&lt;0.001] and overall survival [HR 7.0 (95%CI 3.5-15.1), P&lt;0.001] in patients with metastatic breast cancer.

Conclusion: We demonstrated high rates of brain metastases from a heterogeneous group of cell lines that have not previously been associated with brain metastases, demonstrated miR-141 as a key regulator of brain metastasis and provided clinical evidence supporting the prognostic relevance of miR-141. We propose that miR-141 should be examined as a biomarker and potential target in the prevention and treatment of brain metastases from breast cancer.

Citation Format: Bisrat G Debeb, Lara Lacerda, Simone Anfossi, Parmeswaran Diagaradjane, Khoi Chu, Lei Huo, Caimiao Wei, Richard A Larson, Adam R Wolfe, Wei Xu, Daniel L Smith, Li Li, Cristina Ivan, Pamela K Allen, Xiang H Zhang, George A Calin, Savitri Krishnamurthy, Naoto T Ueno, Thomas A Buchholz, James M Reuben, Wendy A Woodward. The microRNA miR-141 is a key regulator of brain metastasis from breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-16-01.

Abstract P4-01-04: Circulating tumor cells (CTC) are associated with defects in innate and adaptive immunity in inflammatory breast cancer (IBC) patients

Background: CTCs play a crucial role in tumor dissemination and are prognostic factor in primary and metastatic breast cancer patients. Immune cells in peripheral blood (PB) contribute to an unfavorable microenvironment for the CTCs survival. As such, effective host innate and adaptive immune surveillance systems could adversely influence tumor dissemination whereas dysfunctional immune systems could provide a favorable microenvironment for the dissemination of CTCs and cancer progression. This study aimed to correlate CTCs with the functions of innate [natural killer (NK) cells] and adaptive (T-cells) immune effector cells in PB of IBC patients.

Methods: This prospective study included 65 IBC (21 non-metastatic, 14 de novo metastatic and 30 recurrent metastatic) patients treated between October 2008 and April 2012 at the MD Anderson Cancer Center. CTCs were enumerated before patients started a new line of chemotherapy using the CellSearch® system, 33 (50.8%) of patients were treatment naïve at the time of blood collection. The phenotype of T cells, their ability to secrete cytokines following activation through the T-cell receptor (TCR) and the NK cell subsets were analyzed by multiparameter flow cytometry and the results were correlated with CTCs and clinical outcome. For survival analysis immune cell counts were dichotomized to low or high category using the median count.

Results: At least 1 CTC (≥ 1) or ≥ 5 CTCs per 7.5 mL of PB was detected in 40 (61.5%) or 21 (32.3%) of patients, respectively. Patients with at least 1 CTC or ≥ 5 CTCs had a significantly inferior overall survival (OS) [HR=2.48, p=0.003 and HR=1.85, p=0.045] than patients with no CTCs or with &lt;5 CTCs, respectively. There was no correlation between CTCs count and total lymphocytes; however, patients with at least 1 CTC or ≥5 CTCs had significantly lower percentages of CD3+ and CD4+ T-cells compared with patients with no CTCs or &lt; 5 CTCs, respectively. Patients with ≥ 1 CTC, had a lower percentage of TCR-activated CD8+ T-cells producing TNF-α (p=0.03) and IFN-γ (p=0.08), and a higher percentage of T regulatory lymphocytes (p=0.05) compared to patients with undetectable CTCs. Moreover, CTCs ≥5 was inversely associated with the percentage of the following NK cells subsets: non-ADCC NK (Spearman rho' = -0.30, p=0.02), ADCC NK (rho' = -0.15, p=0.20) and exhausted NK (rho = -0.24, p=0.04). We also observed increased prognostic value of CTCs in the context of adaptive immune cells, with worse OS for patients with ≥ 5 CTCs and low count of TCR-activated CD8+ T cells producing TNF-α (HR=6.72, p=0.0007) compared with patients with &lt; 5 CTCs and high count of TCR-activated CD8+ that produced TNF-α.

Conclusions: IBC patients with CTCs in PB had abnormalities in both innate and adaptive immunity as evidenced by low percentages of NK cell subsets, and low percentage of TCR-activated CD8+ T cells producing TNF-α, respectively. These data illustrate an inverse relationship between CTCs and both innate and adaptive immune cells in the PB microenvironment that could potentially impact tumor cell dissemination and initiation of the metastatic cascade. Moreover, immune cell profiling could add further prognostic value to CTCs in IBC patients.

Citation Format: Michal Mego, Hui Gao, Evan N Cohen, Simone Anfossi, Antonio Giordano, Sanda Tin, Tamer M Fouad, Wendy A Woodward, Ricardo H Alvarez, Vicente Valero, Naoto T Ueno, Gabriel N Hortobagyi, Massimo Cristofanilli, James M Reuben. Circulating tumor cells (CTC) are associated with defects in innate and adaptive immunity in inflammatory breast cancer (IBC) patients [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P4-01-04.

Establishment and characterization of a new cell line of canine inflammatory mammary cancer: IPC-366

Canine inflammatory mammary cancer (IMC) shares epidemiologic, histopathological and clinical characteristics with the disease in humans and has been proposed as a natural model for human inflammatory breast cancer (IBC). The aim of this study was to characterize a new cell line from IMC (IPC-366) for the comparative study of both IMC and IBC. Tumors cells from a female dog with clinical IMC were collected. The cells were grown under adherent conditions. The growth, cytological, ultrastructural and immunohistochemical (IHC) characteristics of IPC-366 were evaluated. Ten female Balb/SCID mice were inoculated with IPC-366 cells to assess their tumorigenicity and metastatic potential. Chromosome aberration test and Karyotype revealed the presence of structural aberration, numerical and neutral rearrangements, demonstrating a chromosomal instability. Microscopic examination of tumor revealed an epithelial morphology with marked anysocytosis. Cytological and histological examination of smears and ultrathin sections by electron microscopy revealed that IPC-366 is formed by highly malignant large round or polygonal cells characterized by marked atypia and prominent nucleoli and frequent multinucleated cells. Some cells had cytoplasmic empty spaces covered by cytoplasmic membrane resembling capillary endothelial cells, a phenomenon that has been related to s vasculogenic mimicry. IHC characterization of IPC-366 was basal-like: epithelial cells (AE1/AE3+, CK14+, vimentin+, actin-, p63-, ER-, PR-, HER-2, E-cadherin, overexpressed COX-2 and high Ki-67 proliferation index (87.15 %). At 2 weeks after inoculating the IPC-366 cells, a tumor mass was found in 100 % of mice. At 4 weeks metastases in lung and lymph nodes were found. Xenograph tumors maintained the original IHC characteristics of the female dog tumor. In summary, the cell line IPC-366 is a fast growing malignant triple negative cell line model of inflammatory mammary carcinoma that can be used for the comparative study of both IMC and IBC.

Differential effect of phosphorylation-defective survivin on radiation response in estrogen receptor-positive and -negative breast cancer

Survivin is a key member of the inhibitor of apoptosis protein family, and is considered a promising therapeutic target due to its universal overexpression in cancers. Survivin is implicated in cellular radiation response through its role in apoptosis, cell division, and DNA damage response. In the present study, analysis of publically available data sets showed that survivin gene expression increased with breast cancer stage (p < 0.00001) and was significantly higher in estrogen receptor-negative cancers as compared to estrogen receptor-positive cancers (p = 9e-46). However, survivin was prognostic in estrogen receptor-positive tumors (p = 0.03) but not in estrogen receptor-negative tumors (p = 0.28). We assessed the effect of a survivin dominant-negative mutant on colony-formation (2D) and mammosphere-formation (3D) efficiency, and radiation response in the estrogen receptor-positive MCF7 and estrogen receptor-negative SUM149 breast cancer cell lines. The colony-formation efficiency was significantly lower in the dominant-negative survivin-transduced cells versus control MCF7 cells (0.42 vs. 0.58, p < 0.01), but it was significantly higher in dominant-negative population versus control-transduced SUM149 cells (0.29 vs. 0.20, p < 0.01). A similar, non-significant, trend in mammosphere-formation efficiency was observed. We compared the radiosensitivity of cells stably expressing dominant-negative survivin with their controls in both cell lines under 2D and 3D culture conditions following exposure to increasing doses of radiation. We found that the dominant-negative populations were radioprotective in MCF7 cells but radiosensitive in SUM149 cells compared to the control-transduced population; further, Taxol was synergistic with the survivin mutant in SUM149 but not MCF7. Our data suggests that survivin modulation influences radiation response differently in estrogen receptor-positive and estrogen receptor-negative breast cancer subtypes, warranting further investigation.

The 21-gene recurrence score complements IBTR! Estimates in early-stage, hormone receptor-positive, HER2-normal, lymph node-negative breast cancer

Clinicians have traditionally used clinicopathological (CP) factors to determine locoregional recurrence (LR) risk of breast cancer and have generated the IBTR! nomogram to predict the risk of ipsilateral breast tumor recurrence (IBTR). The 21-gene recurrence score (RS) assay was recently correlated with LR in retrospective studies. The objective of this study was to examine the relationship between the RS and IBTR!. CP characteristics of 308 consecutive patients who underwent RS testing at our institution were examined. IBTR! was used to estimate the risk of 10-year IBTR. Descriptive statistics were used to compare the RS with the estimated IBTR!. Given a low event rate in this cohort, actual IBTR rates were not reported. Most patients had stage I/II (98%) and grade I/II (77%) disease. Median age was 54 years (range, 30–78). Median IBTR! without radiation therapy was 10% (mean, 12% [range, 4-43%]). RS was low (<18), intermediate (18–30), and high (>30) in 52% (n = 160), 40% (n = 123), and 8% (n = 25) patients. Overall, IBTR! did not correlate with RS (P = .77). We saw no correlation between RS and IBTR! in patients with less than (P = .32) or greater than (P = .48) a 10% risk of IBTR. Interestingly, Ki-67 expression correlated with both IBTR! (P = .019) and the RS (P = .002). Further study is warranted to determine if the RS can provide complementary biological information to CP factors in estimating the risk of LR. Prospective studies evaluating this association may potentially allow for individualized treatment decisions.

Circulating tumor cells in newly diagnosed inflammatory breast cancer

Introduction

Circulating tumor cells (CTCs) are an independent prognostic factor for progression-free survival (PFS) and overall survival (OS) in patients with metastatic breast cancer. Inflammatory breast cancer (IBC) is one of the most aggressive forms of breast cancer. The prognostic value of a CTC count in newly diagnosed IBC has not been established. The aim of this study was to assess the prognostic value of a baseline CTC count in patients with newly diagnosed IBC.

Methods

This retrospective study included 147 patients with newly diagnosed IBC (77 with locally advanced and 70 with metastatic IBC) treated with neoadjuvant therapy or first-line chemotherapy during the period from January 2004 through December 2012 at The University of Texas MD Anderson Cancer Center. CTCs were detected and enumerated by using the CellSearch system before patients were started with chemotherapy.

Results

The proportion of patients with ≥1 CTC was lower among patients with stage III than among patients with metastatic IBC (54.5% versus 84.3%; P = 0.0002); the proportion of patients with ≥5 CTCs was also lower for stage III than for metastatic IBC (19.5% versus 47.1%; P = 0.0004). Patients with fewer than five CTCs had significantly better progression-free survival (PFS) (hazard ratio (HR) = 0.60; P = 0.02) and overall survival (HR = 0.59; P = 0.03) than patients with five or more CTCs. Among patients with stage III IBC, there was a nonsignificant difference in PFS (HR = 0.66; 95% confidence interval (CI), 0.31 to 1.39; P = 0.29) and OS (HR = 0.54; 95% CI, 0.24 to 1.26; P = 0.48) in patients with no CTCs compared with patients with one or more CTCs. In multivariate analysis, CTC was prognostic for PFS and OS independent of clinical stage.

Conclusions

CTCs can be detected in a large proportion of patients with newly diagnosed IBC and are a strong predictor of worse prognosis in patients with newly diagnosed IBC.

Web based pathology assessment in RTOG 98-04

Aims

Radiation Therapy Oncology Group 98-04 sought to identify women with ‘good risk’ ductal carcinoma in situ (DCIS) who receive no significant benefit from radiation. Enrolment criteria excluded close or positive margins and grade 3 disease. To ensure reproducibility in identifying good risk pathology, an optional web based teaching tool was developed and a random sampling of 10% of submitted slides were reviewed by a central pathologist.

Methods

Submitting pathologists were asked to use the web based teaching tool and submit an assessment of the tool along with the pathology specimen form and DCIS H&E stained slide. Per protocol pathology was centrally reviewed for 10% of the cases.

Results

Of the 55 DCIS cases reviewed, three had close or positive margins and three were assessed to include grade 3 DCIS, therefore 95% of DCIS cases reviewed were correctly graded, and 89% reviewed were pathologically appropriate for enrolment. Regarding the teaching tool, 13% of DCIS cases included forms that indicated the website was used. One of these seven who used the website submitted DCIS of grade 3.

Conclusions

Central review demonstrates high pathological concordance with enrolment eligibility, particularly with regard to accurate grading. The teaching tool appeared to be underused.

Abstract 4105: Prevalence of breast stem cells in high-risk benign breast lesions and association with breastfeeding

Background: Invasive breast cancers contain a subpopulation of cancer stem cells that are thought to maintain the heterogeneity and self-renewing potential of the tumor. In our previously published data, we demonstrated that stem cells in normal adjacent tissues were associated with triple negative breast cancer. The objective of this study is to determine the presence of stem cells in high risk breast lesions. We hypothesized that stem cells in high-risk lesions and normal adjacent breast tissue may represent a biomarker for increased breast cancer risk. Methods: We identified biopsies from 42 high-risk women seen in the Cancer Prevention Center at The University of Texas MD Anderson Cancer Center between 1988-2011. We collected information on breast cancer risk factors. The biopsies contained high-risk lesions including ductal carcinoma in situ (DCIS) n=21, lobular carcinoma in situ (LCIS) n=5, atypical ductal hyperplasia (ADH) n=7 and atypical lobular hyperplasia (ALH) n=6. The tissues were fluorescently labeled for stem cell markers CD44/CD49f/CD133, and were scored positive if more then 1% cells were positive for all markers using an automated fluorescent microscopy software. The presence of stem cell markers was compared in the normal adjacent tissues and high-risk lesions from a subset of 25 patients. Results: We identified stem cells in 46% of samples containing DCIS, 67% of LCIS, 63% of ALH, and 70% of ADH. There was a 79% concordance in stem cell positive status between the high-risk lesion and adjacent normal tissue. Women with positive stem cell high-risk lesions had no significant difference in age at first birth (24.4 years vs 26.6 years p=0.3), parity (1.7 vs 1.9, p=0.5), or body mass index (27.8 vs 31.8, p=0.07) compared to women without positive stem cell high-risk lesions. Women with positive stem cell high-risk lesions had shorter breastfeeding duration than women without (2.4 months vs 9.0 months p= 0.05). Conclusion: This is the first report, to our knowledge, that stem cells are present in some high-risk lesions and their associated normal breast tissue. Correlation with future development of invasive breast cancer could lay the foundation for future targeted breast cancer prevention strategies.

Citation Format: Rachel L. Atkinson, Fraser Symmans, Therese B. Bevers, Wendy A. Woodward, Abenaa M. Brewster. Prevalence of breast stem cells in high-risk benign breast lesions and association with breastfeeding. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4105. doi:10.1158/1538-7445.AM2014-4105

Cancer stem cell markers are enriched in normal tissue adjacent to triple negative breast cancer and inversely correlated with DNA repair deficiency

Introduction

We hypothesized that cells present in normal tissue that bear cancer stem cell markers may represent a cancer cell of origin or a microenvironment primed for tumor development, and that their presence may correlate with the clinically defined subtypes of breast cancer that show increased tumorigenicity and stem cell features.

Methods

Normal tissues sampled at least 5 cm from primary tumors (normal adjacent tissue) were obtained from 61 chemotherapy-naive patients with breast cancer treated with mastectomy. Samples were stained simultaneously with immunofluorescence for CD44/CD49f/CD133/2 stem cell markers. We assessed the association between CD44⁺CD49f⁺CD133/2⁺ staining in normal adjacent tissue and breast cancer receptor subtype (defined by the expression of the estrogen (ER), progesterone (PR), or human epidermal growth factor-2 (Her2) receptors). We also examined the correlation between CD44⁺CD49f⁺CD133/2⁺ immunofluorescence and each of two previously published gene signatures, one derived from stem-cell enriched tissue and one from BRCA mutated tissue expected to have defective DNA repair.

Results

Patients with triple negative breast cancer (ER^–/PR^–/HER2^–) expressed CD44⁺CD49f⁺CD133/2⁺ in 9 of 9 normal adjacent tissue samples compared with 7 of 52 ER⁺ and/or Her2⁺ tumors (P < 0.001). Further, expression of CD44⁺CD49f⁺CD133/2⁺ by normal adjacent tissue correlated positively with a stem cell-derived tumorigenic signature (P <0.001) and inversely with a defective DNA-repair signature (P <0.001).

Conclusion

Normal cells bearing cancer stem cell markers are associated with the triple negative receptor subtype of breast cancer. This study suggests stem cell staining and gene expression signatures from normal breast tissues represent novel tissue-based risk biomarkers for triple negative breast cancer. Validation of these results in additional studies of normal tissue from cancer-free women could lay the foundation for future targeted triple negative breast cancer prevention strategies.

Factors influencing survival in inflammatory breast cancer

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Background: Inflammatory breast cancer (IBC) is a rare and aggressive form of breast cancer associated with poor prognosis, characterized by rapidly growing mass, skin changes, and regional adenopathy. The objective of this study was to determine if delay in treatment influenced survival in IBC patients. Methods: A prospective IBC database identified 93 women with stage III IBC who received care at MD Anderson from 2007 - 2012 and were retrospectively reviewed. All patients received neoadjuvant chemotherapy followed by surgery, unless progression of disease was noted, and postmastectomy radiation. Impact of time from onset of symptoms to chemotherapy or to surgery on overall survival (OS) and progression free survival (PFS) were evaluated after adjusting for the baseline covariates in the Cox model. Results: A majority of patients were white (77.4%) with an average age of 54 years. Average days from onset of symptoms to first chemo is 95 (range 16 – 387) and to surgery is 283 (range 184 – 585). Four patients had progression while on chemo. There were 14 deaths with median follow up of 2.6 years from diagnosis. In univariate analysis, delay in treatment, > 90 days from onset of symptoms to chemo, did not affect OS or PFS. Obtaining negative margins was statistically significant for OS and PFS measured from first chemo (p=0.005 and p=0.007). Positive HER-2 status was associated with longer PFS time from chemo (p=0.02, log-rank test) and from surgery (p=0.009). Positive progesterone receptor (PR) was found to be statistically significantly associated with longer OS time from chemo (p=0.01) and from surgery (p=0.03). Clinical and imaging response to chemo were associated with better OS (p=0.007 and p=0.005) and pathologic response was marginally associated with improved OS and PFS (p=0.07 and p=0.06), both measured from surgery. In multivariate Cox model, adjusting for PR or HER2, days from onset of symptoms to chemo or surgery did not have significant impact on OS or PFS. Conclusions: While traditionally delay diagnosis and treatment is considered one of the factors associated with poor prognosis, our study suggests otherwise. However, due to such rapid progression of disease, early diagnosis is still important in the overall management of patients diagnosed with IBC.

Implementation of the american college of surgeons oncology group z1071 trial data in clinical practice: is there a way forward for sentinel lymph node dissection in clinically node-positive breast cancer patients treated with neoadjuvant chemotherapy?

For clinically node-positive breast cancer patients receiving neoadjuvant chemotherapy, approximately 40 % will be found to be pathologically node negative. The American College of Surgeons Oncology Group Z1071 trial was therefore conducted to evaluate sentinel lymph node dissection (SLND) in these patients. The trial's primary end point was to determine the false-negative rate (FNR) among patients with clinical N1 disease in whom at least 2 sentinel lymph nodes (SLNs) were identified. The FNR was 12.6 %, which exceeded the prespecified end point of 10.0 %. After data publication, our multidisciplinary team discussed the trial results and how we may incorporate the findings into clinical practice. Patient selection and surgical technique are critical. As an example, when dual tracer technique was used, the FNR was 10.8 %. Data from the trial presented at the San Antonio Breast Cancer Symposium suggested that the FNR could be improved if a clip was placed in the biopsy-proven positive lymph node and removal of that node during SLND was confirmed. Taking this into consideration, we have proposed an approach to surgical management of the axilla in clinically node-positive patients receiving neoadjuvant chemotherapy termed targeted axillary dissection (TAD). TAD involves placing a clip at the time a lymph node is determined to be positive. After completion of neoadjuvant chemotherapy, the clipped node is localized by using a wire or radioactive seed, and during the SLND procedure, all SLNs and the clipped node are removed. We are currently evaluating the efficacy of TAD in axillary staging after neoadjuvant chemotherapy.

EZH2 expression correlates with locoregional recurrence after radiation in inflammatory breast cancer

BACKGROUND

Enhancer of zeste homolog 2 (EZH2), a member of the polycomb group proteins, has been shown to promote cancer progression and breast cancer stem cell (CSC) expansion. Breast CSCs are associated with resistance to radiation in inflammatory breast cancer (IBC), a rare but aggressive variant of breast cancer. In this retrospective study, we examined the clinical role of EZH2 in locoregional recurrence (LRR) of IBC patients treated with radiation.

PATIENTS AND METHODS

62 IBC patients who received radiation (7 pre-operative, 55 post-operative) and had adequate follow up to assess LRR were the subject of this study. Positive EZH2 status was defined as nuclear immunohistochemical staining in at least 10% of invasive cancer cells. Association of EZH2 expression with clinicopathologic features were evaluated using the Chi-square statistic and actuarial LRR free survival (LRFS) was determined using the Kaplan-Meier method.

RESULTS

The median follow-up for this cohort was 33.7 months, and the 5-year overall LRFS rate was 69%. Of the 62 patients, 16 (25.8%) had LRR, and 15 out of 16 LRR occurred in EZH2 expressing cases. Univariate analysis indicated that patients who had EZH2-positive IBC had a significantly lower 5-year locoregional free survival (LRFS) rate than patients who had EZH2-negative IBC (93.3% vs. 59.1%; P = 0.01). Positive EZH2 expression was associated significantly with negative ER status (97.1% in ER- vs 48.1% in ER+; P < 0.0001) and triple-negative receptor status (P = 0.0001) and all triple-negative tumors were EZH2-positive. In multivariate analysis, only triple negative status remained an independent predictor of worse LRFS (hazard ratio 5.64, 95% CI 2.19 - 14.49, P < 0.0001).

CONCLUSIONS

EZH2 correlates with locoregional recurrence in IBC patients who received radiation treatment. EZH2 expression status may be used in addition to receptor status to identify a subset of patients with IBC who recur locally in spite of radiation and may benefit from enrollment in clinical trials testing radiosensitizers.