Ki67 assessment protocol as an integral biomarker for avoiding radiotherapy in the LUMINA breast cancer trial

AIMS

The LUMINA trial demonstrated a very low local recurrence rate in women ≥55 years with low-risk luminal A breast cancer (defined as grade I-II, T1N0, hormone receptor positive, HER2 negative and Ki67 index ≤13.25%) treated with breast-conserving surgery and endocrine therapy (but no other systemic therapy), supporting the safe omission of radiation in these women. Here we describe the protocol for Ki67 assessment, the companion diagnostic used to guide omission of adjuvant radiotherapy.

METHODS

Ki67 immunohistochemistry was performed on full-face sections at one of three regional labs. Pathologists trained in the International Ki67 in Breast Cancer Working Group (IKWG) method demarcated tumour areas on scanned slides and scored 100 nuclei from each of at least five randomly selected 1-mm fields. For cases with high Ki67 heterogeneity, further virtual cores were selected and scored in order to confidently assign a case as luminal A (≤13.25%) or B (>13.25%). Interlaboratory variability was assessed through an annual quality assurance programme during the study period.

RESULTS

From the quality assurance programme, the mean Ki67 index across all cases/labs was 13%. The observed intraclass correlation coefficient (ICC) and kappa statistics were ≥0.9 and ≥0.7, respectively, indicating a substantial level of agreement. Median scoring time was 4 min per case. The IKWG-recommended scoring method, performed directly from slides, requiring up to four scored fields, is concordant with the LUMINA scoring method (ICC ≥ 0.9).

CONCLUSION

Ki67 is a practical, reproducible, and inexpensive biomarker that can identify low-risk luminal A breast cancers as potential candidates for radiation de-escalation.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov number, NCT01791829.

Omitting Radiotherapy after Breast-Conserving Surgery in Luminal A Breast Cancer

BACKGROUND

Adjuvant radiotherapy is prescribed after breast-conserving surgery to reduce the risk of local recurrence. However, radiotherapy is inconvenient, costly, and associated with both short-term and long-term side effects. Clinicopathologic factors alone are of limited use in the identification of women at low risk for local recurrence in whom radiotherapy can be omitted. Molecularly defined intrinsic subtypes of breast cancer can provide additional prognostic information.

METHODS

We performed a prospective cohort study involving women who were at least 55 years of age, had undergone breast-conserving surgery for T1N0 (tumor size <2 cm and node negative), grade 1 or 2, luminal A-subtype breast cancer (defined as estrogen receptor positivity of ≥1%, progesterone receptor positivity of >20%, negative human epidermal growth factor receptor 2, and Ki67 index of ≤13.25%), and had received adjuvant endocrine therapy. Patients who met the clinical eligibility criteria were registered, and Ki67 immunohistochemical analysis was performed centrally. Patients with a Ki67 index of 13.25% or less were enrolled and did not receive radiotherapy. The primary outcome was local recurrence in the ipsilateral breast. In consultation with radiation oncologists and patients with breast cancer, we determined that if the upper boundary of the two-sided 90% confidence interval for the cumulative incidence at 5 years was less than 5%, this would represent an acceptable risk of local recurrence at 5 years.

RESULTS

Of 740 registered patients, 500 eligible patients were enrolled. At 5 years after enrollment, recurrence was reported in 2.3% of the patients (90% confidence interval [CI], 1.3 to 3.8; 95% CI, 1.2 to 4.1), a result that met the prespecified boundary. Breast cancer occurred in the contralateral breast in 1.9% of the patients (90% CI, 1.1 to 3.2), and recurrence of any type was observed in 2.7% (90% CI, 1.6 to 4.1).

CONCLUSIONS

Among women who were at least 55 years of age and had T1N0, grade 1 or 2, luminal A breast cancer that were treated with breast-conserving surgery and endocrine therapy alone, the incidence of local recurrence at 5 years was low with the omission of radiotherapy. (Funded by the Canadian Cancer Society and the Canadian Breast Cancer Foundation; LUMINA ClinicalTrials.gov number, NCT01791829.).

Ovarian cancer pathology characteristics as predictors of variant pathogenicity in BRCA1 and BRCA2

BACKGROUND

The distribution of ovarian tumour characteristics differs between germline BRCA1 and BRCA2 pathogenic variant carriers and non-carriers. In this study, we assessed the utility of ovarian tumour characteristics as predictors of BRCA1 and BRCA2 variant pathogenicity, for application using the American College of Medical Genetics and the Association for Molecular Pathology (ACMG/AMP) variant classification system.

METHODS

Data for 10,373 ovarian cancer cases, including carriers and non-carriers of BRCA1 or BRCA2 pathogenic variants, were collected from unpublished international cohorts and consortia and published studies. Likelihood ratios (LR) were calculated for the association of ovarian cancer histology and other characteristics, with BRCA1 and BRCA2 variant pathogenicity. Estimates were aligned to ACMG/AMP code strengths (supporting, moderate, strong).

RESULTS

No histological subtype provided informative ACMG/AMP evidence in favour of BRCA1 and BRCA2 variant pathogenicity. Evidence against variant pathogenicity was estimated for the mucinous and clear cell histologies (supporting) and borderline cases (moderate). Refined associations are provided according to tumour grade, invasion and age at diagnosis.

CONCLUSIONS

We provide detailed estimates for predicting BRCA1 and BRCA2 variant pathogenicity based on ovarian tumour characteristics. This evidence can be combined with other variant information under the ACMG/AMP classification system, to improve classification and carrier clinical management.

Ki67 in Breast Cancer Assay: An Ad Hoc Testing Recommendation from the Canadian Association of Pathologists Task Force

Ki67, a marker of cellular proliferation, is commonly assessed in surgical pathology laboratories. In breast cancer, Ki67 is an established prognostic factor with higher levels associated with worse long-term survival. However, Ki67 IHC is considered of limited clinical use in breast cancer management largely due to issues related to standardization and reproducibility of scoring across laboratories. Recently, both the American Food and Drug Administration (FDA) and Health Canada have approved the use of abemaciclib (CDK4/6 inhibitor) for patients with HR+/HER2: high-risk early breast cancers in the adjuvant setting. Health Canada and the FDA have included a Ki67 proliferation index of ≥20% in the drug monograph. The approval was based on the results from monarchE, a phase III clinical trial in early-stage chemotherapy-naïve, HR+, HER2 negative patients at high risk of early recurrence. The study has shown significant improvement in invasive disease-free survival (IDFS) with abemaciclib when combined with adjuvant endocrine therapy at two years. Therefore, there is an urgent need by the breast pathology and medical oncology community in Canada to establish national guideline recommendations for Ki67 testing as a predictive marker in the context of abemaciclib therapy consideration. The following recommendations are based on previous IKWG publications, available guidance from the monarchE trial and expert opinions. The current recommendations are by no means final or comprehensive, and their goal is to focus on its role in the selection of patients for abemaciclib therapy. The aim of this document is to guide Canadian pathologists on how to test and report Ki67 in invasive breast cancer. Testing should be performed upon a medical oncologist’s request only. Testing must be performed on treatment-naïve tumor tissue. Testing on the core biopsy is preferred; however, a well-fixed resection specimen is an acceptable alternative. Adhering to ASCO/CAP fixation guidelines for breast biomarkers is advised. Readout training is strongly recommended. Visual counting methods, other than eyeballing, should be used, with global rather than hot spot assessment preferred. Counting 100 cells in at least four areas of the tumor is recommended. The Ki67 scoring app developed to assist pathologists with scoring Ki67 proposed by the IKWG, available for free download, may be used. Automated image analysis is very promising, and laboratories with such technology are encouraged to use it as an adjunct to visual counting. A score of <5 or >30 is more robust. The task force recommends that the results are best expressed as a continuous variable. The appropriate antibody clone and staining protocols to be used may take time to address. For the time being, the task force recommends having tonsils/+pancreas on-slide control and enrollment in at least one national/international EQA program. Analytical validation remains a pending goal. Until the data become available, using local ki67 protocols is acceptable. The task force recommends participation in upcoming calibration and technical validation initiatives.

Abstract P4-02-16: Prognostic and Predictive Capacity of Tumor Infiltrating Lymphocytes in the MA.20 regional radiotherapy trial

Background: The benefit of regional nodal irradiation (RNI) in patients with low burden metastatic axillary disease was established in MA.20 showing that patients randomized to receive adjuvant whole breast irradiation (WBI) plus RNI experienced a significantly better disease free survival (DFS) and distant disease free survival (DDFS) compared to those who received WBI alone and this advantage was maintained in the hormone receptor negative subgroup. Stromal tumor infiltrating lymphocytes (sTILs) have shown prognostic and predictive value in HER2 positive and triple negative breast cancers. To date, clinical importance of immune infiltrates as prognostic and predictive biomarkers in the context of benefit from RNI has not been shown. Methods: 1064 full-face hematoxylin and eosin (H&E) stained sections and formalin fixed paraffin embedded primary tumor blocks assembled into 16 tissue microarrays (TMAs) in quadruplicates linked with clinical data were accessible from the original 1832 patients in the MA.20 trial for this retrospective-prospective translational study conducted according to the REMARK guidelines. sTILs were assessed on scanned images of H&E sections according to the International Immuno-Oncology Working Group method, and on TMAs by CD8 immunohistochemistry (IHC) using a validated assay. Biomarkers were scored by pathologists blinded to the clinical data and analyzed as continuous and categorical variables using prespecified median cutpoints. The median follow-up was 9.5 years. Cox proportional regression modelling was used after adjusting for clinicopathological factors and treatments. Hazard ratios (HR) with 95% confidence intervals (CI) were reported for the primary endpoint of DFS and secondary endpoint of DDFS. Predictive value was assessed by the interaction test between the treatment arm and the biomarkers in the full cohort and an IHC defined non-luminal A subgroup. Results: 1035 cases were evaluable for sTILs on H&E sections. Of these 52.6% (n=544) cases with ≥10% sTILs displayed a significant correlation with age &lt; 50 years, grade III, tumor size &gt;2cm, hormone receptor negative status, and non-luminal A subgroup (p &lt; 0.05). Of the 857 evaluable cases on TMAs, CD8+sTILs (≥16) were observed in 49.8% (n=427) cases and showed a significant association with grade III, ER negativity and non-luminal A status (p &lt; 0.05). For the full cohort, H&E sTILs assessed as a continuous parameter, were not prognostic for DFS (HR 0.993; 95% CI 0.984-1.003; p=0.18) but provided prognostic information for DDFS (HR 0.988; 95% CI 0.977-0.999; p=0.04) in multivariate analyses. H&E sTILs did not show predictive value as a continuous variable. Similarly, using the prespecified cutpoint (≥10%), H&E sTILs were neither prognostic nor predictive. Increasing level of CD8+sTILs was associated with significantly improved DFS (HR 0.99; 95% CI 0.983-0.998; p=0.02) and DDFS (HR 0.98; 95% CI 0.97-0.99; p=0.002) in multivariate analyses. For the full cohort, CD8+sTILs as a continuous variable, showed a significant improvement in DDFS for patients randomized to WBI and RNI (HR 0.979; 95%CI 0.959-0.999; p(interaction) =0.04) compared to WBI alone and a trend (HR 0.977; 95%CI 0.954-1.001; p(interaction) =0.06) for better outcome was observed for the non-luminal A subgroup. CD8+sTILs at the prespecified cutpoint (≥16) were not prognostic or predictive. Conclusions: Pre-treatment tumoral infiltration with stromal lymphocytes provided positive prognostic information for DFS (CD8+sTILs) and DDFS (H&E sTILs and CD8+sTILs) when examined as a continuous variable but failed to do so at prespecified cutpoints. While CD8+sTILs as a continuous variable predicted benefit from RNI, significant prediction results were not seen for prespecified cutpoint or related biomarker H&E sTIL. These results require further validation.

Citation Format: Nazia Riaz, Bingshu Chen, Anita Bane, Dongxia Gao, Elisabeth Stovgaard, Zuzana Kos, Samuel Leung, Elahe Shenasa, Wendy Parulekar, Shelley Chambers, Torsten Nielson, Timothy J. Whelan. Prognostic and Predictive Capacity of Tumor Infiltrating Lymphocytes in the MA.20 regional radiotherapy trial [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-02-16.

Abstract P6-04-02: Ki67 Assessment Protocol: Companion Diagnostic Biomarker for LUMINA Prospective Cohort Study

Introduction: Luminal A breast cancer is associated with low proliferation, indolent disease biology and limited benefit from chemotherapy. The LUMINA prospective study recently demonstrated a very low 5 year local recurrence rate (2.3%) in women ≥55 years with grade I-II, T1N0 luminal A breast cancer (defined as ER ≥ 1%, PR&gt;20%, HER2 negative and Ki67 index ≤ 13.25%) treated with breast conservation surgery and endocrine therapy without radiation, supporting the safe omission of radiation in this molecularly defined low risk group. Here, we report the protocol for multicentre Ki67 scoring, the embedded integral companion diagnostic employed in LUMINA. Methodology: Ki67 immunohistochemistry was performed on full-face sections at one of the 3 labs and scored by pathologists using an adaptation of the International Ki67 Working Group (IKWG) method. Prior to the start of the study, quality assurance and quality control programs were set up to standardize staining and scoring protocols. All pathologists completed the IKWG training and calibration exercise using a tissue microarray-based series of 18 breast cancers. Inter-laboratory variability was assessed annually during the study period on a set of 9 breast cancer cases with a range of Ki67 scores that purposely over-represented the 13.25% threshold. Stained slides were scanned and images annotated to demarcate invasive carcinoma. Next, 5 random, non-overlapping, 1 mm virtual cores were generated via software and 100 nuclei assessed per core using a keyboard-based counting aid. Ki67 index was derived as the percentage of all counted tumor nuclei that are positively stained. For cases with high Ki67 heterogeneity, additional virtual cores were generated and scored and a 95% confidence interval (CI) of Ki67 index was estimated. The goal was to confidently assign a case as luminal A (≤13.25%) or B (&gt; 13.5%). If the 95% CI crossed 13.25% a recount was performed by an additional pathologist. Results: Quality Assurance Programs: Mean Ki67 index across all cases, labs and years was 13% with high concordance across specimens and score ranges. Observed intra-class correlation coefficients (ICC) were ≥ 0.9, showing near perfect agreement in quantitative Ki67 evaluation. About the 13.25% cutpoint, the observed Kappa statistics were ≥ 0.7 indicating excellent agreement for assignment of luminal A vs. B status. A sub-study was conducted to compare the method of randomly selected virtual fields with the IKWG ‘global weighted score’ method for visual assessment of full-face sections. For this purpose, the 9 quality control cases were reassessed by the same pathologist using the updated IKWG method. Results showed an ICC of 0.96 (0.95% CI: 0.91-0.98) indicating that the Ki67 score generated by the methodology employed in LUMINA trial is highly concordant with the IKWG scoring methodology validated for use on full face sections. Ki67 index summary statistics across LUMINA: Of the 724 eligible cases, 69% (n=500) were assigned as luminal A (median Ki67=7.5%; IQR 5.2-9.8%) and 31% (n=224) as luminal B (median Ki67=19%; IQR 17-23%). Median pathologist scoring time was 4 minutes/case; 45% of cases required scoring of &gt; 5 virtual cores. Per protocol, 39% cases where the initial CI crossed 13.25% were rescored by additional pathologist for final luminal A consensus assignment. Conclusions: Ki67 is a practical biomarker for identifying molecularly defined low-risk luminal A cancers. Our structured quality assurance approach for the trial led to excellent reproducibility and concordance among decentralized labs, supporting applicability of a distributed, inexpensive methodology beyond clinical trial settings and in resource restricted environments.

Citation Format: Torsten Nielson, Samuel Leung, Nazia Riaz, Zuzana Kos, Anita Bane, Timothy J. Whelan. Ki67 Assessment Protocol: Companion Diagnostic Biomarker for LUMINA Prospective Cohort Study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-04-02.

LUMINA: A prospective trial omitting radiotherapy (RT) following breast conserving surgery (BCS) in T1N0 luminal A breast cancer (BC)

LBA501

Background: Adjuvant breast RT is usually prescribed following BCS to reduce the risk of local recurrence (LR). However, this treatment is inconvenient, costly, and associated with acute and late toxicity. Traditional clinical pathological factors (CPFs) alone are limited in their ability to identify women with a low enough risk of LR to omit RT. Molecular defined intrinsic subtypes of BC provide additional prognostic information with luminal A having the lowest risk of recurrence. A retrospective analysis of a previous trial suggested that women >60 years with luminal A grade 1-2 T1N0 BC treated by BCS and endocrine therapy alone had a low rate of LR ( JCO 2015; 33:2035). The utility of identifying luminal A subtype combined with CPFs has not been prospectively evaluated for its ability to guide RT decision-making. Methods: A prospective multicenter cohort study was performed. Eligibility criteria were: women ≥ 55 years; having undergone BCS for grade 1-2 T1N0 BC; ≥ 1mm margins of excision; luminal A subtype (defined as: ER ≥ 1%, PR>20%, HER2 negative and Ki67 ≤ 13.25%); and treated with adjuvant endocrine therapy. ER, PR and HER2 were performed locally as per ASCO guidelines. Patients meeting clinical eligibility with ER ≥ 1%, PR>20%, HER2 negative BC were registered and had Ki67 immunohistochemistry performed centrally in one of three Canadian laboratories using International Ki67 Working Group methods. Proficiency testing between laboratories was performed yearly. Patients with Ki67 ≤ 13.25% were enrolled in the trial and were assigned to not receive RT. The primary outcome was LR defined as time from enrollment to any invasive or non-invasive cancer in the ipsilateral breast. Assuming a 5-year LR rate of 3.5%, 500 patients were required to show that the upper bound of a two sided 90% (one-sided 95%) confidence interval (CI) was <5%. Patients were followed every six months for the first two years and then yearly. The probability of LR was estimated using the cumulative incidence function with death as a competing risk. Secondary outcomes were contralateral BC; relapse free survival (RFS) based on any recurrence; disease free survival (DFS) based on any recurrence, second cancer or death; and overall survival (OS). Results: From August 2013 to July 2017, 501 of 727 registered patients from 26 centers had a Ki67 ≤ 13.25% and were enrolled. Median follow-up was 5 years. Median age was 67 and 442 (88%) patients were <75 years. Median tumor size was 1.1 cm. The 5-year rate of LR satisfied our pre-specified boundary (see Table). Conclusions: Women ≥ 55 years with grade 1-2 T1N0 luminal A BC following BCS treated with endocrine therapy alone had very low rates of LR at 5 years and are candidates for omission of RT. Clinical trial information: NCT01791829. [Table: see text]

Cctg MA.39 tailor RT: A randomized trial of regional radiotherapy in biomarker low-risk node-positive breast cancer (NCT03488693)

TPS602

Background: Biomarker low risk, ER positive (+), HER2 negative (-) breast cancer with low burden nodal involvement may be associated with good outcomes (Woodward 2016, Mamounas 2017). There is conflicting data regarding the efficacy of regional radiotherapy after breast conserving surgery (BCS) or mastectomy in these patients (Kyndi 2008, Whelan 2015, Poortmans 2015, Liu 2015). Our hypothesis is that the risk of recurrence in patients with biomarker low risk, ER+, Her2- breast cancer and involvement of 1-3 lymph nodes where regional RT is omitted will not be inferior to the risk of recurrence in patients treated with regional RT. Methods: MA39 is a Canadian Cancer Trials Group led, NCTN sponsored, randomized phase III study comparing breast cancer recurrence free interval (BCRFI) in patients with ER+, Her2-, LN 1-3+ breast cancer that is low risk as defined by Oncotype Dx Recurrence Score < 18. Secondary objectives include a comparison of DFS, breast cancer mortality, OS, locoregional and distant recurrence free intervals, toxicity, arm volume and mobility measurements, patient reported outcomes and cost effectiveness. Key eligibility criteria include: age ≥ 40 years; BCS or mastectomy with axillary dissection and 1-3 positive axillary nodes; BCS and SLNB alone and 1-2 positive axillary nodes; mastectomy and SLNB alone and only 1 positive axillary node; planned endocrine therapy ≥ 5 years; adjuvant chemotherapy allowed. Statistical design: The primary analysis will be a test of non-inferiority (NI) in the intention to treat population. If the upper bound of a one-sided 95% interval for the hazard ratio for BCRFI is < 1.4, NI will be declared. Using a one-sided α of 0.05 and a power of 87%, it is anticipated that 278 events are required. With an expected 5 years of accrual and 4.5 years of follow-up, 2140 patients are needed for the final sample size. Conduct to Date: Study activation May 30 2018. Participation as of February 2019: Registrations 64 Randomizations 26. CIRB approval for continuation of MA.39 was received on January 11 2019. Clinical trial information: NCT03488693.

Abstract 2648: Prognostic significance of thyroid hormone receptor-alpha-2 (THRα2) expression in triple-negative breast cancer: A TCGA study

Background: Thyroid hormones promote breast cancer cell proliferation and expression of their cognate nuclear receptors has shown prognostic potential in small cohort studies. Among two isoforms of thyroid hormone receptor alpha (THRα), the alpha1 splice variant (THRα1) promotes thyroid hormone mediated cell proliferation whereas the alpha2 variant (THRα2) opposes it. Hence, THRα2 expression may be a favorable prognostic biomarker in breast cancer.

Methods: A publicly available database of breast tumors archived by The Cancer Genome Atlas (TCGA) was employed for this study. We analyzed RNA expression of THRα1 and THRα2 in 106 triple negative breast cancers (TNBCs) and correlated it with tumor stage (I vs II vs III) and nodal involvement (positive vs negative). Tumor grade was not uniformly reported. Univariate Cox proportional hazards regression models were fitted to determine the prognostic impact of THRα1 and THRα2 expression on overall survival (OS) and multivariate models were adjusted for age, tumor stage and radiation treatment.

Results: The median age of women was 54 (range 29-90) and 12.3% died. The majority (62.3%) of patients presented with stage II disease; 16.0% were stage III and 17.9% were stage I at diagnosis. There was no significant correlation between THRα1 or THRα2 expression and tumor stage or nodal involvement. Expression of THRα2 was associated with improved OS in both uni- and multi-variate models (Table).

Conclusions: In this study, THRα2 expression was independently prognostic for improved OS in TNBC. We previously demonstrated similar results in 158 TNBCs via immunohistochemistry but differentiation between RNA (as opposed to protein) splice variants is more precise. These results support investigation of THRα2 up-regulation or THRα1 inhibition as therapeutic strategies.

Table. Prognostic associations of THRα2 expression in TNBCVariableUnivariate HR (95%CI)p valueMultivariate HR (95%CI)p valueLog (THRα2)0.46 (0.26-0.81)&lt;0.010.28 (0.09-0.84)0.02Log (THRα1)0.54 (0.31-0.94)0.031.38 (0.53-3.62)0.51Age (years)0.98 (0.94-1.02)0.370.92 (0.84-1.01)0.10Stage (I vs II vs III vs IV)6.14 (2.19-17.22)&lt;0.0126.03 (4.05-167.14)&lt;0.01Radiation therapy (yes vs no)0.23 (0.04-1.22)0.080.10 (0.02-0.73)0.02

Citation Format: Katarzyna J. Jerzak, Anna Dvorkin-Gheva, Jessica G. Cockburn, Anita Bane, John A. Hassell. Prognostic significance of thyroid hormone receptor-alpha-2 (THRα2) expression in triple-negative breast cancer: A TCGA study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2648.

Oral Contraceptive Use and Breast Cancer Risk: Retrospective and Prospective Analyses From a BRCA1 and BRCA2 Mutation Carrier Cohort Study

BACKGROUND

For BRCA1 and BRCA2 mutation carriers, the association between oral contraceptive preparation (OCP) use and breast cancer (BC) risk is still unclear.

METHODS

Breast camcer risk associations were estimated from OCP data on 6030 BRCA1 and 3809 BRCA2 mutation carriers using age-dependent Cox regression, stratified by study and birth cohort. Prospective, left-truncated retrospective and full-cohort retrospective analyses were performed.

RESULTS

For BRCA1 mutation carriers, OCP use was not associated with BC risk in prospective analyses (hazard ratio [HR] = 1.08, 95% confidence interval [CI] = 0.75 to 1.56), but in the left-truncated and full-cohort retrospective analyses, risks were increased by 26% (95% CI = 6% to 51%) and 39% (95% CI = 23% to 58%), respectively. For BRCA2 mutation carriers, OCP use was associated with BC risk in prospective analyses (HR = 1.75, 95% CI = 1.03 to 2.97), but retrospective analyses were inconsistent (left-truncated: HR = 1.06, 95% CI = 0.85 to 1.33; full cohort: HR = 1.52, 95% CI = 1.28 to 1.81). There was evidence of increasing risk with duration of use, especially before the first full-term pregnancy (BRCA1: both retrospective analyses, P < .001 and P = .001, respectively; BRCA2: full retrospective analysis, P = .002).

CONCLUSIONS

Prospective analyses did not show that past use of OCP is associated with an increased BC risk for BRCA1 mutation carriers in young middle-aged women (40-50 years). For BRCA2 mutation carriers, a causal association is also not likely at those ages. Findings between retrospective and prospective analyses were inconsistent and could be due to survival bias or a true association for younger women who were underrepresented in the prospective cohort. Given the uncertain safety of long-term OCP use for BRCA1/2 mutation carriers, indications other than contraception should be avoided and nonhormonal contraceptive methods should be discussed.

Serotonergic system antagonists target breast tumor initiating cells and synergize with chemotherapy to shrink human breast tumor xenografts

Breast tumors comprise an infrequent tumor cell population, termed breast tumor initiating cells (BTIC), which sustain tumor growth, seed metastases and resist cytotoxic therapies. Hence therapies are needed to target BTIC to provide more durable breast cancer remissions than are currently achieved. We previously reported that serotonergic system antagonists abrogated the activity of mouse BTIC resident in the mammary tumors of a HER2-overexpressing model of breast cancer. Here we report that antagonists of serotonin (5-hydroxytryptamine; 5-HT) biosynthesis and activity, including US Federal Food and Drug Administration (FDA)-approved antidepressants, targeted BTIC resident in numerous breast tumor cell lines regardless of their clinical or molecular subtype. Notably, inhibitors of tryptophan hydroxylase 1 (TPH1), required for 5-HT biosynthesis in select non-neuronal cells, the serotonin reuptake transporter (SERT) and several 5-HT receptors compromised BTIC activity as assessed by functional sphere-forming assays. Consistent with these findings, human breast tumor cells express TPH1, 5-HT and SERT independent of their molecular or clinical subtype. Exposure of breast tumor cells ex vivo to sertraline (Zoloft), a selective serotonin reuptake inhibitor (SSRI), reduced BTIC frequency as determined by transplanting drug-treated tumor cells into immune-compromised mice. Moreover, another SSRI (vilazodone; Viibryd) synergized with chemotherapy to shrink breast tumor xenografts in immune-compromised mice by inhibiting tumor cell proliferation and inducing their apoptosis. Collectively our data suggest that antidepressants in combination with cytotoxic anticancer therapies may be an appropriate treatment regimen for testing in clinical trials.

A role of SIPL1/SHARPIN in promoting resistance to hormone therapy in breast cancer

SIPL1 inhibits PTEN function and stimulates NF-κB signaling; both processes contribute to resistance to hormone therapy in estrogen receptor positive breast cancer (ER+ BC). However, whether SIPL1 promotes tamoxifen resistance in BC remains unclear. We report here that SIPL1 enhances tamoxifen resistance in ER+ BC. Overexpression of SIPL1 in MCF7 and TD47 cells conferred tamoxifen resistance. In MCF7 cell-derived tamoxifen resistant (TAM-R) cells, SIPL1 expression was upregulated and knockdown of SIPL1 in TAM-R cells re-sensitized the cells to tamoxifen. Furthermore, xenograft tumors produced by MCF7 SIPL1 cells but not by MCF7 empty vector cells resisted tamoxifen treatment. Collectively, we demonstrated a role of SIPL1 in promoting tamoxifen resistance in BC. Increases in AKT activation and NF-κB signaling were detected in both MCF7 SIPL1 and TAM-R cells; using specific inhibitors and unique SIPL1 mutants to inhibit either pathway significantly reduced tamoxifen resistance. A SIPL1 mutant defective in activating both pathways was incapable of conferring resistance to tamoxifen, showing that both pathways contributed to SIPL1-derived resistance to tamoxifen in ER+ BCs. Using the Curtis dataset of breast cancer (n=1980) within the cBioPortal database, we examined a correlation of SIPL1 expression with ER+ BC and resistance to hormone therapy. SIPL1 upregulation strongly associates with reductions in overall survival in BC patients, particularly in patients with hormone naïve ER+ BCs. Taken together, we provide data suggesting that SIPL1 contributes to promote resistance to tamoxifen in BC cells through both AKT and NF-κB actions.

Historical epidemiology of hepatitis C virus in select countries-volume 4

Due to the introduction of newer, more efficacious treatment options, there is a pressing need for policy makers and public health officials to develop or adapt national hepatitis C virus (HCV) control strategies to the changing epidemiological landscape. To do so, detailed, country-specific data are needed to characterize the burden of chronic HCV infection. In this study of 17 countries, a literature review of published and unpublished data on HCV prevalence, viraemia, genotype, age and gender distribution, liver transplants and diagnosis and treatment rates was conducted, and inputs were validated by expert consensus in each country. Viraemic prevalence in this study ranged from 0.2% in Hong Kong to 2.4% in Taiwan, while the largest viraemic populations were in Nigeria (2 597 000 cases) and Taiwan (569 000 cases). Diagnosis, treatment and liver transplant rates varied widely across the countries included in this analysis, as did the availability of reliable data. Addressing data gaps will be critical for the development of future strategies to manage and minimize the disease burden of hepatitis C.

The present and future disease burden of hepatitis C virus infections with today's treatment paradigm: Volume 4

Factors influencing the morbidity and mortality associated with viremic hepatitis C virus (HCV) infection change over time and place, making it difficult to compare reported estimates. Models were developed for 17 countries (Bahrain, Bulgaria, Cameroon, Colombia, Croatia, Dominican Republic, Ethiopia, Ghana, Hong Kong, Jordan, Kazakhstan, Malaysia, Morocco, Nigeria, Qatar and Taiwan) to quantify and characterize the viremic population as well as forecast the changes in the infected population and the corresponding disease burden from 2015 to 2030. Model inputs were agreed upon through expert consensus, and a standardized methodology was followed to allow for comparison across countries. The viremic prevalence is expected to remain constant or decline in all but four countries (Ethiopia, Ghana, Jordan and Oman); however, HCV-related morbidity and mortality will increase in all countries except Qatar and Taiwan. In Qatar, the high-treatment rate will contribute to a reduction in total cases and HCV-related morbidity by 2030. In the remaining countries, however, the current treatment paradigm will be insufficient to achieve large reductions in HCV-related morbidity and mortality.

Strategies to manage hepatitis C virus infection disease burden-Volume 4

The hepatitis C virus (HCV) epidemic was forecasted through 2030 for 17 countries in Africa, Asia, Europe, Latin America and the Middle East, and interventions for achieving the Global Health Sector Strategy on viral hepatitis targets-"WHO Targets" (65% reduction in HCV-related deaths, 90% reduction in new infections and 90% of infections diagnosed by 2030) were considered. Scaling up treatment and diagnosis rates over time would be required to achieve these targets in all but one country, even with the introduction of high SVR therapies. The scenarios developed to achieve the WHO Targets in all countries studied assumed the implementation of national policies to prevent new infections and to diagnose current infections through screening.

Ex vivo expanded natural killer cells from breast cancer patients and healthy donors are highly cytotoxic against breast cancer cell lines and patient-derived tumours

BACKGROUND

Natural killer (NK) cells play a critical role in cancer immunosurveillance. Recent developments in NK cell ex-vivo expansion makes it possible to generate millions of activated NK cells from a small volume of peripheral blood. We tested the functionality of ex vivo expanded NK cells in vitro against breast cancer cell lines and in vivo using a xenograft mouse model. The study aim was to assess functionality and phenotype of expanded NK cells from breast cancer patients against breast cancer cell lines and autologous primary tumours.

METHODS

We used a well-established NK cell co-culture system to expand NK cells ex vivo from healthy donors and breast cancer patients and examined their surface marker expression. Moreover, we tested the ability of expanded NK cells to lyse the triple negative breast cancer and HER2-positive breast cancer cell lines MDA-MB-231 and MDA-MB-453, respectively. We also tested their ability to prevent tumour growth in vivo using a xenograft mouse model. Finally, we tested the cytotoxicity of expanded NK cells against autologous and allogeneic primary breast cancer tumours in vitro.

RESULTS

After 3 weeks of culture we observed over 1000-fold expansion of NK cells isolated from either breast cancer patients or healthy donors. We also showed that the phenotype of expanded NK cells is comparable between those from healthy donors and cancer patients. Moreover, our results confirm the ability of ex vivo expanded NK cells to lyse tumour cell lines in vitro. While the cell lines examined had differential sensitivity to NK cell killing we found this was correlated with level of major histocompatibility complex (MHC) class I expression. In our in vivo model, NK cells prevented tumour establishment and growth in immunocompromised mice. Finally, we showed that NK cells expanded from the peripheral blood of breast cancer patients show high cytotoxicity against allogeneic and autologous patient-derived tumour cells in vitro.

CONCLUSION

NK cells from breast cancer patients can be expanded similarly to those from healthy donors, have a high cytotoxic ability against breast cancer cell lines and patient-derived tumour cells, and can be compatible with current cancer treatments to restore NK cell function in cancer patients.

Association of breast cancer risk in BRCA1 and BRCA2 mutation carriers with genetic variants showing differential allelic expression: identification of a modifier of breast cancer risk at locus 11q22.3

PURPOSE

Cis-acting regulatory SNPs resulting in differential allelic expression (DAE) may, in part, explain the underlying phenotypic variation associated with many complex diseases. To investigate whether common variants associated with DAE were involved in breast cancer susceptibility among BRCA1 and BRCA2 mutation carriers, a list of 175 genes was developed based of their involvement in cancer-related pathways.

METHODS

Using data from a genome-wide map of SNPs associated with allelic expression, we assessed the association of ~320 SNPs located in the vicinity of these genes with breast and ovarian cancer risks in 15,252 BRCA1 and 8211 BRCA2 mutation carriers ascertained from 54 studies participating in the Consortium of Investigators of Modifiers of BRCA1/2.

RESULTS

We identified a region on 11q22.3 that is significantly associated with breast cancer risk in BRCA1 mutation carriers (most significant SNP rs228595 p = 7 × 10-6). This association was absent in BRCA2 carriers (p = 0.57). The 11q22.3 region notably encompasses genes such as ACAT1, NPAT, and ATM. Expression quantitative trait loci associations were observed in both normal breast and tumors across this region, namely for ACAT1, ATM, and other genes. In silico analysis revealed some overlap between top risk-associated SNPs and relevant biological features in mammary cell data, which suggests potential functional significance.

CONCLUSION

We identified 11q22.3 as a new modifier locus in BRCA1 carriers. Replication in larger studies using estrogen receptor (ER)-negative or triple-negative (i.e., ER-, progesterone receptor-, and HER2-negative) cases could therefore be helpful to confirm the association of this locus with breast cancer risk.

A phase II trial of dovitinib in previously-treated advanced pleural mesothelioma: The Ontario Clinical Oncology Group

OBJECTIVES

Following failure of a platinum-antifolate combination regimen, there is no standard therapy for advanced malignant pleural mesothelioma (MPM). The fibroblast growth factor receptor (FGFR) signaling pathways may be a relevant target in MPM. Dovitinib inhibits multiple tyrosine receptor kinases, predominantly the vascular endothelial growth factor receptors (VEGFR), but also FGFRs, and could be active in MPM.

METHODS

This open-label multicentre phase II trial [NCT01769547] enrolled fit, consenting adult patients with advanced MPM who had previously received platinum-antifolate combination chemotherapy and up to one additional line of systemic therapy. Dovitinib was administered orally at 500mg/day for 5days on, 2days off, in 28-day cycles. Response was assessed every 2 cycles using RECIST 1.1 criteria modified for MPM. Correlative studies included FGFR-1 amplification on archival tumour and serum samples for circulating angiogenesis factors. The primary end-point was the proportion of patients progression-free at 3 months (PF3) using a two-stage design.

RESULTS

12 patients (10 males, median age 67) were enrolled. The median number of cycles administered was 2.5 (range 1-8). One unconfirmed partial response was observed. PF3 was 50% (95% confidence interval 28.4% to 88.0%); although the criterion for proceeding to stage II accrual was met, the trial was halted due to a combination of minimal activity with several early progression events and poor tolerability in this patient population. One of 12 tumour specimens had low amplification of FGFR-1.

CONCLUSIONS

Dovitinib has minimal activity in previously-treated MPM. The role of the FGFR pathway in MPM remains unclear.

The effects of lymph node status on predicting outcome in ER+ /HER2- tamoxifen treated breast cancer patients using gene signatures

BACKGROUND

Lymph node (LN) status is the most important prognostic variable used to guide ER positive (+) breast cancer treatment. While a positive nodal status is traditionally associated with a poor prognosis, a subset of these patients respond well to treatment and achieve long-term survival. Several gene signatures have been established as a means of predicting outcome of breast cancer patients, but the development and indication for use of these assays varies. Here we compare the capacity of two approved gene signatures and a third novel signature to predict outcome in distinct LN negative (-) and LN+ populations. We also examine biological differences between tumours associated with LN- and LN+ disease.

METHODS

Gene expression data from publically available data sets was used to compare the ability of Oncotype DX and Prosigna to predict Distant Metastasis Free Survival (DMFS) using an in silico platform. A novel gene signature (Ellen) was developed by including patients with both LN- and LN+ disease and using Prediction Analysis of Microarrays (PAM) software. Gene Set Enrichment Analysis (GSEA) was used to determine biological pathways associated with patient outcome in both LN- and LN+ tumors.

RESULTS

The Oncotype DX gene signature, which only used LN- patients during development, significantly predicted outcome in LN- patients, but not LN+ patients. The Prosigna gene signature, which included both LN- and LN+ patients during development, predicted outcome in both LN- and LN+ patient groups. Ellen was also able to predict outcome in both LN- and LN+ patient groups. GSEA suggested that epigenetic modification may be related to poor outcome in LN- disease, whereas immune response may be related to good outcome in LN+ disease.

CONCLUSIONS

We demonstrate the importance of incorporating lymph node status during the development of prognostic gene signatures. Ellen may be a useful tool to predict outcome of patients regardless of lymph node status, or for those with unknown lymph node status. Finally we present candidate biological processes, unique to LN- and LN+ disease, that may indicate risk of relapse.

Identification and evaluation of network modules for the prognosis of basal-like breast cancer

Purpose

Basal-like breast cancer (BLBC) is a molecular subtype of breast cancer associated with poor clinical outcome, although some patients with BLBC experience long-term survival. Apart from nodal status, current clinical/histopathological variables show little capacity to identify BLBC patients at either high- or low-risk of disease recurrence. Accordingly, we sought to develop a network based genomic predictor for predicting the outcome of patients with BLBC.

Experimental Design

We performed network analysis on global gene expression profiling data of BLBCs, and identified BLBC network modules associated with AP-1 transcription, G-protein coupled receptors, and T-, B-, and NK-cells that are significant predictors of BLBC patient survival.

Results

In gene expression and tissue microarray (TMA) validation cohorts of 210 and 102 BLBC patients, respectively, the identified network modules were robustly associated with patient outcome. In the gene expression validation cohort, the Kaplan-Meier estimate for 10-year survival in the low-risk group was 90%, whereas in the high-risk group it was a 56%. In the TMA cohort, the Kaplan-Meier estimate for 10-year survival in the low-risk group was 98%, whereas in the high-risk group it was 71%.

Conclusions

The capacity to distinguish between patients with BLBC at high- or low-risk of recurrence at the time of diagnosis could permit timely intervention with more aggressive therapeutic regimens in those patients predicted to be high-risk, and to avoid such therapy in low-risk patients.

Factors Promoting Tamoxifen Resistance in Breast Cancer via Stimulating Breast Cancer Stem Cell Expansion

Estrogen receptor-alpha positive (ER(+)) breast cancer constitutes 70-75% of the disease incidence. Tamoxifen has been the basis of endocrine therapy for patients with ER(+) breast cancer for more than three decades. The treatment reduces the annual mortality rate of breast cancer by 31%, and remains the most effective targeted cancer therapy. However, approximately one-third of patients treated with adjuvant tamoxifen suffer from aggressive recurrent disease. Resistance to tamoxifen, thus, remains a major challenge in providing effective treatments for these patients. In an effort to overcome the resistance, intensive research has been conducted to understand the underlying mechanisms; this has resulted in the identification of complex factors/pathways contributing to tamoxifen resistance, including modulations of the ERsignaling, upregulation of a set of growth factor receptor networks (HER2, EGFR, FGFR, and IGF1R), alterations of the PI3K-PTEN/AKT/mTOR pathway, and an elevation of the NF-κB signaling. Despite these advances, our understanding of the acquired resistance remains fragmented and there is a lack of a platform to integrate these diversified molecular factors/ pathways into a cohesive mechanistic model. Nonetheless, at the cellular level, it is becoming increasingly recongnized that cancer stem cells (CSCs) are key in driving cancer metastasis and therapy resistance. Likewise, evidence is emerging for the critical contributions of breast cancer stem cells (BCSCs) to tamoxifen resistance. In this review, we will discuss these recent developments of BCSC-mediated resistance to tamoxifen and the contributions of those demonstrated molecular factors/pathways to BCSC expansion during the emergency of tamoxifen resistance.

Male breast cancer in BRCA1 and BRCA2 mutation carriers: pathology data from the Consortium of Investigators of Modifiers of BRCA1/2

BACKGROUND

BRCA1 and, more commonly, BRCA2 mutations are associated with increased risk of male breast cancer (MBC). However, only a paucity of data exists on the pathology of breast cancers (BCs) in men with BRCA1/2 mutations. Using the largest available dataset, we determined whether MBCs arising in BRCA1/2 mutation carriers display specific pathologic features and whether these features differ from those of BRCA1/2 female BCs (FBCs).

METHODS

We characterised the pathologic features of 419 BRCA1/2 MBCs and, using logistic regression analysis, contrasted those with data from 9675 BRCA1/2 FBCs and with population-based data from 6351 MBCs in the Surveillance, Epidemiology, and End Results (SEER) database.

RESULTS

Among BRCA2 MBCs, grade significantly decreased with increasing age at diagnosis (P = 0.005). Compared with BRCA2 FBCs, BRCA2 MBCs were of significantly higher stage (P for trend = 2 × 10(-5)) and higher grade (P for trend = 0.005) and were more likely to be oestrogen receptor-positive [odds ratio (OR) 10.59; 95 % confidence interval (CI) 5.15-21.80] and progesterone receptor-positive (OR 5.04; 95 % CI 3.17-8.04). With the exception of grade, similar patterns of associations emerged when we compared BRCA1 MBCs and FBCs. BRCA2 MBCs also presented with higher grade than MBCs from the SEER database (P for trend = 4 × 10(-12)).

CONCLUSIONS

On the basis of the largest series analysed to date, our results show that BRCA1/2 MBCs display distinct pathologic characteristics compared with BRCA1/2 FBCs, and we identified a specific BRCA2-associated MBC phenotype characterised by a variable suggesting greater biological aggressiveness (i.e., high histologic grade). These findings could lead to the development of gender-specific risk prediction models and guide clinical strategies appropriate for MBC management.

Abstract 4346: Prognostic gene signature for intermediate risk prostate cancer

The over treatment of prostate cancer patients is a significant concern, as recent clinical trials suggest that many patients are over treated which can lead to significant patient morbidity. Although the Gleason score is a powerful predictor of lethal or indolent disease, a significant proportion (∼40%) of men present with early stage Gleason score (GS) 7 tumors, for whom prognosis is variable. The goal of this study is to develop and optimize a robust prognostic gene signature that can be utilized on formalin fixed paraffin embedded (FFPE) core biopsy tumor material to better classify patients with intermediate risk, GS 7 tumors into good and poor outcome groups.

Three gene signatures were derived from publicly available gene expression profiles of the Swedish Watchful Waiting cohort. The Genomic Grade Index consisted of the top 25 molecular signatures discriminating between high (8, 9 & 10) and low (≤ 6) GS tumors. The Lethal Gene Score consisted of the top 25 molecular signatures discriminating between lethal and indolent disease within GS 7 tumors only. A network-based gene signature consisted of 88 genes which accurately stratified GS 7 patients into high risk and low risk groups, resembling the survival curves of high GS and low GS patients. The prognostic capacity of the combined gene signature was tested in silico on the gene expression profiles of the Mayo cohort. Results demonstrated the gene signature's highly robust capacity for differentiating low risk and high risk patients within GS 7 patients.

The NanoString nCounter System will be used to quantify mRNA from prostate FFPE blocks to assess the expression of the 138 prognostic genes. 156 archived prostate tumor blocks will be collected from intermediate risk, GS 7 patients enrolled in the 2005 PR5 prostate trial, which also collected 12 years of clinical follow-up information. Results will be correlated with biochemical (PSA) failure rates and overall survival.

In short, our findings provide proof-of-principle that through the use of gene signatures it is possible to separate prostate cancer patients of intermediate risk into good and poor outcome groups. Furthermore, they also identify multiple gene candidates whose expression could likely be formulated into a clinically applicable assay, the implementation of which could serve to stratify prostate cancer patients with tumors of intermediate risk into more accurate high and low risk groups.

Citation Format: Brian Li, Robin Hallet, Ying Wu, Greg Pong, John Hassell, Sebastien Hotte, Mark Levine, Himansu Lukka, Anita Bane. Prognostic gene signature for intermediate risk prostate cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4346. doi:10.1158/1538-7445.AM2015-4346

Abstract 5289: The role of the immune system in lymph node positive ER+ breast cancer

Estrogen receptor (ER) positive breast cancer (BC) accounts for 70% of BC diagnoses and is associated with a good outcome when treated with conventional therapies, including tamoxifen. However, there remains a sub-population of patients who undergo relapse within 10 years of diagnosis and do not respond well to standard therapies. While lymph node (LN) status is an important indicator of poor prognosis, additional information is needed to more accurately predict patients who will or will not relapse. Previous genomic studies from our lab have shown that immune response is an important feature of LN+ BCs that do not relapse. In addition, other studies have also examined the role of the immune system in ER+ BC, but due to varying study designs, it is unclear how immune response pertains to ER+ BC relapse. The goal of this project is to characterize immune response in ER+ BC by measuring levels of immune markers using immunohistochemistry (IHC) and RNA expression levels and comparing those to tumour characteristics. We have developed a cohort of retrospective ER+ BC patients with tumour samples available through the Hamilton Health Science tumour bank. Patients were selected for eligibility based on ER status, early stage disease, and having long term clinical follow-up. Clinical charts for each patient were reviewed and pathological, treatment, and outcome data were abstracted. Tumour blocks were obtained and sections stained for haematoxylin and eosin were marked for tumour boarders then used to construct Tissue microarrays (TMA) for IHC assays and RNA is to be extracted from each tumour block. 318 patient samples have been obtained that meet eligibility requirements. Among those, 163 are LN- and 110 are LN+, and the remainder have unknown LN status. Primary endpoint for this study is the development of distant metastasis. Roughly 10% of LN- patients developed distant metastasis within 10 years and roughly 20% of LN+ patients developed distant metastasis. In total, 14% of patients came to endpoint during the study period. TMAs were stained for pathological markers, including ER, PR, HER2, and Ki67 as well as immune markers such as CD8 and CD20. RNA expression levels for each of these were also determined and both were compared with clinical outcome. Here we present a retrospective cohort of ER+ BC patients with 10 years of clinical follow-up data that can be used for IHC and RNA analysis. Further, we have examined the association between immune response and prognosis in lymph node positive ER+ BC patients.

Citation Format: Jessica G. Cockburn, Amy Gillgrass, Anita Bane. The role of the immune system in lymph node positive ER+ breast cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5289. doi:10.1158/1538-7445.AM2015-5289

Amelanotic Melanoma Presenting with Plasmacytoid Morphology and BRAF V600 Mutation

Plasmacytoid melanoma is an unusual variant of malignant melanoma. The plasmacytoid morphology can be found in a variety of other malignancies including carcinomas, plasma cell neoplasms, lymphoproliferative disorders, and sarcomas. The authors report a rare case of plasmacytoid amelanotic malignant melanoma in a 78-year-old man presenting with an enlarging palpable, erythematous mass on his left posterior shoulder. A fine needle aspirate showed atypical findings with single amelanotic cells with high nuclear to cytoplasmic ratio, mono- and multi-nucleation with prominent nucleoli and intranuclear inclusions. Review of the excision and immunohistochemical analysis revealed the malignant plasmacytoid cells stained with vimentin, S-100, HMB-45, and other staining patterns consistent with melanoma. Initial evaluation was negative for other sites of disease. However, 4 months later, the patient was noted to have metastatic disease to his lungs and liver. Given that the tumor was noted to be BRAF V600R mutated, the patient was started on single agent dabrafenib. The plasmacytoid morphology can be found in a variety of malignancies. Melanoma should be considered in the differential diagnosis of any malignancy presenting with plasmacytoid features.

Abstract C184: Thyroid hormone receptors: Future targets for breast cancer therapy?

Introduction: Thyroid receptors (TR) have been documented in breast cancer tissue. Given their role in cell metabolism and proliferation, they may serve as future therapeutic targets. Prior to targeting TRs for therapy, their prevalence and degree of expression must be elucidated. In this study, the expression and sub-cellular location of three TR isoforms (TRA1, TRA2, TRB1) in breast cancer tissue is documented and correlated to standard pathological and clinical prognostic markers.

Methods: 131 archived breast tumors were selected sequentially starting from January 2007, to allow for collection of 5-year overall survival (OS) and disease-free survival (DFS) data. The tumors were assessed retrospectively for TRA1, TRA2 and TRB1 expression by immunohistochemistry, using commercially available antibodies. Nuclear versus cytoplasmic location was noted. The Allred score of each tumor was assessed in triplicate; an average score ≥5 was considered significant in the statistical analysis. TR expression was correlated with pathological markers (ER/PR and Her2/neu positivity, tumor size, grade, nodal involvement, lymphovascular invasion, mitotic count) and clinical factors (age, OS, DFS) using correlation analyses and binary regression models.

Results: The age of patients was 65±15 (mean± standard deviation) years. The majority had T1c (31%) or T2 (56%) disease, and 39% had lymph node involvement. 60% of tumors were ER positive and 13% were Her2/neu positive. TRs were expressed to some extent in 130 of 131 assessed breast tumors; TRA1 was highly expressed (Allred score ≥5) in 81% of tumors, while TRA2 and TRB1 were highly expressed in 51% and 29% of tumors, respectively. TRA1 and TRA2 were expressed in the nucleus, while 95% of TRB1 receptors were expressed in the cytoplasm. Cytoplasmic TRB1 expression was associated with a mitotic count &lt;10 [OR 0.4 (95%CI 0.20-0.93), p=0.03], but not with other variables. High TRA2 expression was associated with ER [OR 5.5 (95%CI 2.2-13.7), p&lt;0.01] and PR [OR 5.3 (95%CI 2.4-11.8), p&lt;0.01] positivity, and also 5-year DFS [OR 2.6 (95%CI 1.1-6.1), p=0.03]. Conversely, low TRA expression was associated with Her2/neu positivity [OR 3.2, (95%CI 1.0-9.5), p=0.04], high tumor grade [OR 6.0, (95%CI 2.3-15.2), p&lt;0.01] and a mitotic count &gt;10 [OR 2.8, (95%CI 1.4-5.8), p=0.05]. There was no significant association between TR expression and tumor size, lymph node involvement or OS.

Conclusion: Thyroid receptors are widely expressed in breast cancer and they are known to influence cellular proliferation. High TRA2 expression is statistically significant in predicting favorable pathologic markers and even 5-year DFS. As with ER, its favorable prognostic profile should not exclude TRA2 as a therapeutic target; it may have the potential to expand our armamentarium of hormone directed therapies.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):C184.

Citation Format: Katarzyna J. Jerzak, Anita Bane, Bindi Dhesy-Thind. Thyroid hormone receptors: Future targets for breast cancer therapy?. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr C184.

Abstract A022: The use of LN status on developing prognostic gene signatures for ER+ breast cancer

Introduction: Estrogen Receptor (ER) positive Breast Cancers account for approximately 70% of all breast cancers and have a better prognosis than ER- breast cancer. These patients are amenable to endocrine treatment, including tamoxifen, which eliminates recurrence in a large group of patients, but approximately 30% will relapse within 15 years of diagnosis. The most important predictor of recurrence in ER+ breast cancer is lymph node (LN) status. Patients with LN metastases (LN+) have increased risk of systemic recurrence, compared to ER+ patients without LN metastases (LN-). However, it is difficult for clinicians to determine appropriate treatment for ER+ LN+ breast cancer, so this group is generally treated aggressively. Several commercially available molecular signatures have been developed to predict outcome of early stage breast cancers, but none have been exclusively designed for ER+ breast cancer patients, inclusive of lymph node status.

Methods: Here, three publicly available datasets (Gene Expression Omnibus, NCBI), consisting of gene expression profiles from primary ER+ breast cancer tumours were used to develop prognostic gene signatures. Patients from these cohorts were treated exclusively with tamoxifen for 5 years and were followed for at least 10 years past diagnosis. Gene expression significantly related to high risk of distant metastasis free survival (DMFS) of patients from our training cohort, at 10 years, was examined using the Prediction Analysis of Microarray (PAM, Stanford) and used to comprise our novel molecular signatures. Three independent signatures were developed using cohorts of patients with LN- disease exclusively, LN+ disease exclusively, or combined lymph node status. The performance of these signatures was evaluated using an independent cohort of patients with either LN- or LN+ disease. We also examined biologically relevant pathways, using Gene Set Enrichment Analysis (GSEA, Broad Institute), to examine whether the heterogeneous nature of ER+ breast cancers can be related to phenotype or outcome.

Results: Gene expression and DMFS data from LN-, LN+, or combined patient samples were evaluated to identify sets of genes that predict patient outcome. The LN- signature could accurately predict DMFS of LN- patients from independent cohorts, but was unable to assign LN+ patients to low and high risk of DMFS groups. Similarly, the LN+ signature could accurately predict outcome of LN+ patients, but not LN- patients. Conversely, the combined signature was able to predict DMFS of all patients, regardless of LN status. We further evaluated gene set enrichment and found differences in gene sets associated with LN- and LN+ disease and with different outcomes.

Conclusions: This research demonstrates the importance of considering the lymph node status of patients with both developing and employing prognostic gene signatures to predict outcome of early stage ER+ breast cancer patients. Also, it appears that the development of a signature using an exclusive population (i.e. LN-) of patients is not optimal to predict outcome in patients with different pathological parameters. In the future, using a combined gene signature may help direct treatment decisions for patients with early stage ER+ breast cancer. Further, understanding the biological heterogeneity of this disease, through GSEA, may lead to discovery of appropriate therapeutic targets for patients.

Citation Format: Jessica G. Cockburn, Robin M. Hallett, John A. Hassell, Anita Bane. The use of LN status on developing prognostic gene signatures for ER+ breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr A022.

Abstract A124: Characterization of claudin-low breast cancers

Molecular profiling of human breast cancers has defined 5 molecular subtypes: luminal A, luminal B, HER2 over-expressing, basal-like and claudin-low. The claudin-low subtype was identified in 2007 and is characterized by low expression of claudin proteins, E-cadherin and markers of luminal differentiation, and is reported to be associated with expression of mesenchymal and cancer stem cell (CSC) markers. The prevalence of this subtype is reported to be between 7-14% and there are an excess of tumors with metaplastic and medullary-like features, an association with poor prognosis and evidence that they may be resistant to conventional chemotherapies. Using information from publicly available gene expression microarray data, we sought to identify immunohistochemical markers of the claudin-low subtype and to further describe the morphological features of claudin-low breast tumors and the overall survival characteristics of patients with these tumors, along with any associations between these tumors and CSC markers.

Using the gene expression microarray datasets, we performed hierarchical clustering to assign a molecular subtype to the tumors. Differential gene expression analysis was used to identify genes that were significantly upregulated and downregulated between claudin-low tumors and other tumor subtypes as candidates for immunohistochemical markers for our formalin fixed paraffin embedded (FFPE) tumor cohort. We utilized 943 stage I or stage II, lymph node negative primary invasive breast cancers treated with breast conserving surgery and adjuvant radiation, which had FFPE tumor blocks available for tissue microarray construction. On the basis of IHC expression of ER, PR, HER2, Ki67, EGFR, CK5/6, Claudin proteins and E-cadherin, tumors were classified as luminal A, luminal B, HER2 over-expressing, basal-like or claudin-low. Kaplan-Meier methods were used to estimate overall survival, and Fisher's exact tests were used to compare tumor characteristics and expression of CSC markers (ALDH1, CD44hi/CD24low) between claudin-low and luminal A tumors. Claudin-low tumors comprised 8% of our cohort with an overall survival of 73.6% at a median follow up of 12 years, similar to that of basal-like and HER2 over-expressing subtypes. Compared to luminal A type tumors, the claudin-low tumors were statistically more likely to have circumscribed tumor margins. However, there was no statistically significant association between claudin-low subtype and the expression of CSC markers. The claudin-low subtype represents a minority of invasive breast cancers, however this group is characterized by poor prognosis, and as such the identification of these tumors is useful to determine treatment options in the clinical setting.

Citation Format: Kay Dias, Anna Dvorkin-Gheva, Greg Pond, Mark Levine, Timothy Whelan, Anita Bane. Characterization of claudin-low breast cancers. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr A124.

Clinical-pathologic significance of cancer stem cell marker expression in familial breast cancers

Human breast cancer cells with a CD44⁺/CD24^−/low or ALDH1+ phenotype have been demonstrated to be enriched for cancer stem cells (CSCs) using in vitro and in vivo techniques. The aim of this study was to determine the association between CD44⁺/CD24^−/low and ALDH1 expression with clinical–pathologic tumor characteristics, tumor molecular subtype, and survival in a well characterized collection of familial breast cancer cases. 364 familial breast cancers from the Ontario Familial Breast Cancer Registry (58 BRCA1-associated, 64 BRCA2-associated, and 242 familial non-BRCA1/2 cancers) were studied. Each tumor had a centralized pathology review performed. TMA sections of all tumors were analyzed for the expression of ER, PR, HER2, CK5, CK14, EGFR, CD44, CD24, and ALDH1. The Chi square test or Fisher’s exact test was used to analyze the marker associations with clinical–pathologic tumor variables, molecular subtype and genetic subtype. Analyses of the association of overall survival (OS) with marker status were conducted using Kaplan–Meier plots and log-rank tests. The CD44⁺/CD24^−/low and ALDH1+ phenotypes were identified in 16% and 15% of the familial breast cancer cases, respectively, and associated with high-tumor grade, a high-mitotic count, and component features of the medullary type of breast cancer. CD44⁺/CD24^−/low and ALDH1 expression in this series were further associated with the basal-like molecular subtype and the CD44⁺/CD24^−/low phenotype was independently associated with BRCA1 mutational status. The currently accepted breast CSCs markers are present in a minority of familial breast cancers. Whereas the presence of these markers is correlated with several poor prognostic features and the basal-like subtype of breast cancer, they do not predict OS.

Giant cell temporal arteritis associated with overlying basal cell carcinoma: co-incidence or connection?

Giant cell arteritis is a granulomatous vasculitis of large and medium sized arteries manifesting as temporal arteritis and/or polymyalgia rheumatica. The histological assessment of temporal artery biopsies is frequently encountered in anatomical pathology and has important diagnostic consequences in patients clinically suspected of having giant cell arteritis. We present an intriguing case of giant cell arteritis associated with a Basal cell carcinoma and discuss the ongoing controversy pertaining to the association of giant cell arteritis/polymyalgia rheumatica with malignancy.

Abstract 3663: A gene signature for predicting outcome in patients with basal-like breast cancer

Basal-like breast cancer is a molecular subtype of breast cancer generally thought to have a universally poor prognosis. Subsequent studies examining the long-term outcome in thousands of patients with basal-like breast cancer have shown that these patients can be separated into two clinically distinct groups: those likely to experience a systemic recurrence and succumb to their disease within the first 5 years and those expected to show excellent long term survival. The ability to distinguish between these two sub-groups (good and poor prognosis) of basal-like breast cancer patients at the time of initial diagnosis would permit tailoring more aggressive therapeutic regimens to those patients with an inherently poorer prognosis and conversely to avoid such therapy in patients with a more indolent course. We aimed to identify a gene signature that could predict the clinical outcome of basal-like breast cancer patients. To this end we mined publicly available human breast tumor gene expression profiling data and identified patients with basal-like breast cancer. We divided these patients into training and validation sets to identify and confirm the accuracy of a prognostic signature. We identified 137 basal-like breast tumors among 995 breast tumor gene expression profiles. We used 85 of these samples as a training group and identified an optimal 14-gene signature, which accurately identified patients that experienced poor and good long-term survival. We confirmed the accuracy of our gene signature on a 49 patient independent validation set. Importantly, we also confirmed the capacity of our signature to predict outcome in a chemotherapy naïve 27 patient sub-set of the 49 patients validation set.

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 3663. doi:1538-7445.AM2012-3663

Amplification of the Prolactin Receptor Gene in Mammary Lobular Neoplasia

Background: Lobular carcinoma in situ (LCIS) has long been considered a marker of increased risk of cancer in both breasts. However, recent studies have shown that it can behave as a non-obligate precursor lesion as well. The biology and natural history of LCIS still remains ill defined in part because it is a challenging lesion to study as it usually does not have an identifiable gross appearance and is only recognized in fixed tissue specimens.Material and Methods: Using array comparative genomic hybridization (aCGH) we have analyzed regions of amplification found in LCIS and adjacent invasive lobular carcinoma (ILC) in a series of thirteen cases of archival patient samples from our institution. Degenerate oligonucleotide primed (DOP) PCR was performed for whole genome amplification of the extracted DNA from microdissected tissue samples prior to microarray analysis. Analysis of microarray data was performed using Significance Analysis of Microarrays (SAM). Of the ten most amplified genes in LCIS (highest SAM scores), one was selected for quantitative real time PCR (Q-PCR) validation due to the limited amount of material available from these cases. Q-PCR validation was performed on samples from 8 cases of LCIS and invasive lobular carcinoma and 12 archival cases of ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) for comparison.Results: Amongst the 10 genes with the highest SAM scores, the prolactin receptor gene (PRLR) was selected for further Q-PCR validation in our limited samples. Amplification of PRLR was confirmed by Q-PCR in 4/8 (50%) of cases of LCIS and 4/8 (50%) cases of ILC, compared to 0/12 (0%) cases of DCIS and 3/12 (25%) cases of IDC. When LCIS and ILC were combined into one group, there was more amplification of the prolactin receptor gene when compared to the DCIS and IDC group (p= 0.01). The level of amplification between the two groups also differed in the range of copy number values, which was lower in the ductal group (0.78-1.58, n=24) compared to the lobular group (0.92-3.68, n=16) (p&lt;0.05).Conclusion: We have identified the prolactin receptor as a potential molecular target in lobular neoplasia using array comparative genomic hybridization. In contrast, we have shown that the prolactin receptor may not be as important for the progression of ductal lesions. These results support the view that lobular and ductal carcinoma evolve along separate pathways. Validation of the expression of PRLR in a larger number of LCIS cases is warranted.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4151.

An update on apocrine lesions of the breast

Apocrine change occurs in a spectrum of benign lesions in the female breast and is also demonstrated in a subgroup of in situ and invasive carcinomas. Recent research has focused on the molecular phenotype of both benign and malignant apocrine lesions. This review will briefly summarize the morphological characteristics and risk associations of the spectrum of apocrine proliferations, but will focus on the updated molecular studies of both in situ and invasive apocrine carcinomas.

BRCA1 and BRCA2 mutation carriers, oral contraceptive use, and breast cancer before age 50

BACKGROUND

Understanding the effect of oral contraceptives on risk of breast cancer in BRCA1 or BRCA2 mutation carriers is important because oral contraceptive use is a common, modifiable practice.

METHODS

We studied 497 BRCA1 and 307 BRCA2 mutation carriers, of whom 195 and 128, respectively, had been diagnosed with breast cancer. Case-control analyses were conducted using unconditional logistic regression with adjustments for family history and familial relationships and were restricted to subjects with a reference age under 50 years.

RESULTS

For BRCA1 mutation carriers, there was no significant association between risk of breast cancer and use of oral contraceptives for at least 1 year [odds ratio (OR), 0.77; 95% confidence interval (95% CI), 0.53-1.12] or duration of oral contraceptive use (P(trend) = 0.62). For BRCA2 mutation carriers, there was no association with use of oral contraceptives for at least 1 year (OR, 1.62; 95% CI, 0.90-2.92); however, there was an association of elevated risk with oral contraceptive use for at least 5 years (OR, 2.06; 95% CI, 1.08-3.94) and with duration of use (OR(trend) per year of use, 1.08; P = 0.008). Similar results were obtained when we considered only use of oral contraceptives that first started in 1975 or later.

CONCLUSIONS

We found no evidence overall that use of oral contraceptives for at least 1 year is associated with breast cancer risk for BRCA1 and BRCA2 mutation carriers before age 50. For BRCA2 mutation carriers, use of oral contraceptives may be associated with an increased risk of breast cancer among women who use them for at least 5 years. Further studies reporting results separately for BRCA1 and BRCA2 mutation carriers are needed to resolve this important issue.

Linear IgA Disease Presenting as Desquamative Gingivitis

Linear IgA disease is a subepidermal blistering disorder of unknown cause. Along with dermatologic blistering, other manifestations include oral ulceration and desquamative gingivitis. We present a case of linear IgA disease that manifested simply as oropharyngeal ulceration and desquamative gingivitis, resulting in considerable delay in diagnosis and treatment. This article (1) highlights the difficulties of diagnosing linear IgA disease when the predominant presenting features are mucosal and (2) reviews the current literature regarding linear IgA disease.

Case of tuberous sclerosis

Tuberous Sclerosis (TSc) is a benign multi-system hamaertomatosis and is one of the neurocutaneous syndromes (2, 3, 7). The first case of tuberous sclerosis in a 27 years old female patient is reported from Ethiopia. The importance of meticulous evaluation of a patient as a whole to reach at the right diagnosis is stressed. The clinicopathological features of tuberous sclerosis are discussed with literature review.

Adverse effects of dextromethorphan on the spatial learning of rats in the Morris water maze

The effects of the non-competitive NMDA receptor antagonist dextromethorphan on spatial learning were assessed using the Morris water maze. Dextromethorphan was administered to 4 groups of rats in 10, 20, 30, and 40 mg/kg doses. An additional group of rats was administered saline to serve as a vehicle control group. Dextromethorphan impaired learning dose dependently in the initial training phase of the experiment. During the probe trial, dose-dependent performance deficits were noted in the first 15 s of the trial only. Search strategy differences between the lowest and highest dose groups were also observed during the probe trial. During the reversal training phase, when the platform was moved to a new location, the dose-dependent impairment was seen again, but the 40 mg/kg group perseverated to the former location longer than the other groups. A cued control trial indicated that in addition to the learning impairment produced, the highest dose of dextromethorphan may also impair sensory-motor coordination.

Abnormal spermatozoa, testicular degeneration, and varicocele in a ram

A 4-year-old Corriedale ram, with a history of infertility, had 50% abnormal acrosomes in the ejaculate resembling knobbed spermatozoa. Electron microscopic profiles of the apical segment of the affected acrosomes revealed a membrane-enclosed inclusion or cyst filled with particulate matter. The abnormal acrosomes were combined with a high prevalence of other degenerative changes such as head abnormalities, proximal droplets, and loose heads. Spermatozoa were examined from 9 ejaculates collected over an 8-month period. Abnormal acrosomes decreased to 5% after 4 months, but increased to 83% a month later. Examination of the testes after castration revealed bilateral varicocele and degeneration of seminiferous epithelium.

Changes in the morphology of spermatozoa during their passage through the genital tract in dairy bulls with normal and impaired spermat ogenesis

An investigation was conducted on changes in sperm morphology along the excurrent duct of bulls. The study comprised 20 bulls with proven fertility and normal semen picture, and 10 bulls with pathologic semen. The morphology of spermatozoa was evaluated on ejaculates and on postslaughter collected contents from the excurrent duct. The incidence of pathologic sperm heads decreased along the duct in both groups of bulls. The main decrease generally occurred in caput epididymidis. In bulls with pathologic semen, the decrease continued in lower regions of epididymis and was deferens. The rate and pattern of sperm removal seem to primarily depend on the quality of spermatozoa entering the excurrent duct. The removal was clearly selective and is assumed to be associated with phagocytosis of spermatozoa mainly in the efferent ductules and proximal part of caput epididymis. Proximal cytoplasmic droplets were present on almost all sperm in the efferent ductules. The incidence decreased during passage along the genital tract. Migration of cytoplasmic droplets from a proximal to a distal position took place between regions C and D of the caput epididymidis. The incidence of middle-piece abnormalities decreased during passage along the genital tract, while the incidence of sperm tail abnormalities increased in the corpus and cauda epididymidis in all bulls.

The effect of two different feed levels on the development of the reproductive organs in boars

The aim of the present investigation was to study the development of the reproductive organs in boars fed restrictively and fed ad libitum. A total of 120 boars were purchased by the experimental station at 20 kg live weight. Three groups of 4 litter mates were selected after each of 10 A.I. boars (7 Swedish Landrace and 3 Swedish Yorkshire). The dams were unselected sows from pigletproducing herds. Two boar pigs from each litter were allocated at random among 2 treatment groups. One group ( = N) was fed restrictively and the other group (=A) ad libitum. The boars were slaughtered at 90 kg or at 120 kg live weight. The reproductive organs were removed at slaughter and examined.

The ad libitum fed boars were about 2 weeks younger at slaughter than those fed restrictively (16.5 and 13.7 days respectively for the 2 weight classes). The weights of the testes were somewhat higher for ad libitum fed than for restrictively fed boars. Out of 94 examined pairs of testes, epididymides, seminal vesicles and bulbo-urethral glands, the left was heavier than the right in 68%, 62%, 48%, and 36%, respectively. Fewer (4/23) ad libitum fed than restrictively fed boars (9/26) had reached puberty at 90 kg live weight. Age at puberty thus seems to be less variable than body size in boars.