Citations

Abstract Background: The Preoperative Endocrine Prognostic Index (PEPI) is a method to predict outcome after neoadjuvant endocrine therapy that integrates Ki67, estrogen receptor (ER) analysis and pathological stage from the surgical specimen (Ellis, JNCI 100:1380, 2008). We sought to further develop the PEPI for use in clinical trials by: a) establishing an efficient SOP for Ki67 analysis, b) determining the effect of simplifying the score by removing the ER component (modified "mPEPI") and c) independent validation of mPEPI in the ACOSOG (Alliance) Z1031 neoadjuvant aromatase inhibitor trial (Ellis, M, JCO 29:234, 2011). Methods: Ki-67 assay development focused on reproducing a 2.7% Ki-67 cut point (CP) required for PEPI. Ventana Image analysis (IA) to replace labor-intensive visual point counting (VPC) was assessed to increase scoring efficiency. Discordant scores led to a triage approach where cases with complex histological features that could not be resolved by IA were flagged for VPC. The Ki-67 scoring approach was preliminarily validated on T1/2 N0 cases from the P024 and POL trials (SABCS 2013, abstract P3-05-190). Models with and without ER suggested ER was dispensable. A locked SOP for mPEPI was subsequently applied to the Z1031A trial. The primary endpoint was time from the date of surgery to local, regional, or distant recurrence in the mPEPI-0 group (T1/2 N0, Ki67 <2.7%) versus the mPEPI>0 group. Results. mPEPI by IA was evaluated on 202 of 377 (53%) patients enrolled into Z1031A (6% of IA results were triaged to VPC). All patients have been followed a minimum of 2 years (median: 5 years; max: 7 years). Only 10 patients in the mPEPI-0 group (22.7%) received adjuvant chemotherapy, versus 78 in the mPEPI>0 group (49.4%). Time to breast cancer recurrence was decreased among those with mPEPI>0 status relative to those with mPEPI-0 status (log rank p=0.012). Only one disease event among 44 (2%) cases with mPEPI-0 was observed versus 26 of 158 cases with mPEPI>0 (16.5%) Conclusions. mPEPI-0 status can identify patients at low risk of relapse after neoadjuvant endocrine therapy: therefore mPEPI-0 status has operational characteristics similar to pCR after chemotherapy for ER-negative disease. mPEPI is undergoing prospective validation in the Alliance ALTERNATE trial that will assess whether Fulvestrant increases the mPEPI-0 rate and also will prospectively determine whether patients with mPEPI-0 status can safely be managed without adjuvant chemotherapy treatment. Citation Format: Souzan Sanati, Vera J Suman, Rodrigo Goncalves, Katherine DeSchryver, Cynthia X Ma, Jeremy Hoog, Erika Crouch, Michael Barnes, Gary Unzeitig, A Marilyn Leitch, Kelly K Hunt, Matthew J Ellis. Validation of the preoperative endocrine prognostic index in the ACOSOG (Alliance) Z1031 neoadjuvant aromatase inhibitor trial [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 P4-11-13.

Abstract [Background] Patient advocates bring a unique, valuable perspective and presence to SPOREs. However, although patient advocates are recommended members of SPORE grants, guidelines are not given on the role of advocates or on measurement of the performance of advocates. [Methods] The Mayo Clinic Breast Cancer SPORE Patient Advocate Advisory Committee has developed a participation measurement tool. This tool will underpin and augment evaluations of the individual advocate contributions by the program PI and the SPORE project leaders. The Advocate Advisory Committee Chair will review the evaluations with the individual advocates. Annually, the advocate committee will review the performance of the group by the standard of the metrics. [Results] Advocates kept a log of their SPORE activities for four months then worked with a statistician to discern patterns of measurable, evaluable behaviors. The determined evaluable areas are training, scientific activity, meeting attendance, communication. Currently, those metrics are being tracked. Advocates developed the metrics together and report activities at the monthly advocate meetings. Currently, activities are simply tracked and categorized. No minimum standards are set. This will be the third step in the development of the metrics. [Conclusions] This approach is the first step in the development of meaningful evaluation of advocate SPORE activities. It quantifies the participation of advocates in the SPORE and provides the basis for developing a qualitative performance evaluation. The SPORE PI and the Committee Chair will use the evaluations to interpret the involvement of advocates in SPORE research and activities and to plan interventions to strengthen the advocate contributions to the SPORE. Citation Format: Cynthia Chauhan, Wayland Eppard, Lori Denison, Debra Gearhart, Lawanna Holmes, Ruth Kraft, Linda Miller, Mary A Sitta, Mary L Smith, James Ingle, Matthew Goetz. Measurements of advocate participation in and contributions to the Mayo Clinic breast cancer SPORE [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 P2-09-04.

Abstract Neoadjuvant endocrine therapy (ET) in patients (pts) with locally advanced estrogen receptor positive (ER+) breast cancer (BC) improves breast conservation rate, and importantly offers an opportunity for individualized assessment of tumor responsiveness to ET to guide subsequent treatment. Previous neoadjuvant ET trials demonstrated that pathologic tumor size (pT), axillary lymph node status (N), and tumor Ki67 value at surgery predicted risk of relapse. Preoperative endocrine prognostic index (PEPI) was therefore developed to assign risk scores based on these factors. Modified PEPI 0, defined by pT1-2 N0 Ki67< 2.7%, was associated with extremely low risk of recurrence without adjuvant chemotherapy. In addition, high Ki67 post 2-4 weeks (wks) of neoadjuvant ET identified resistant tumors with poor outcome. ALTERNATE trial is a three-arm phase III neoadjuvant/adjuvant ET trial designed to achieve two primary objectives. The first is to prospectively validate that modified PEPI 0 predicts > 95% relapse-free survival (RFS). The second is to determine whether fulvestrant (F), or fulvestrant (F) plus anastrozole (A), is superior to A in inducing a higher rate of modified PEPI 0. Secondary objectives include assessing RFS for pts with endocrine resistant tumor, defined by Ki67 > 10% at 4 or 12 wk, disease progression, or modified PEPI non-0, and pathologic responses of resistant tumors to neoadjuvant chemotherapy. Correlative studies include degrees of Ki67 suppression and ER level post treatment. In addition, ongoing research sequencing studies of DNA and RNA will be performed to contrast sensitive vs resistant tumors. During the first phase of the trial, 1200 pts are randomized 1:1:1 to the F, A or F/A. This provides an 82% chance, 1-sided alpha 0.025 chi-square test to detect at least 10% difference in modified PEPI 0 rate comparing F or F/A with A. While waiting for result of analysis, the A arm will continue for the 2nd phase enrollment. Only the F-containing arm(s) superior over A will be continued to the 2nd phase. During the 2nd phase, an additional 540 pts in each arm is estimated to obtain 317 pts with PEPI score 0. This will have a 90% chance, with a one-sided alpha=0.025 nonparametric Brookmeyer-Crowley type one sample survival test, rejecting that 5 year RFS rate is 95%. The maximum sample size is 2820 pts. Eligible pts include postmenopausal women with newly diagnosed clinical stage II or III ER+ (Allred score 6-8) HER2- BC. Tumor biopsy is required at baseline, 4 wk, and surgery for central Ki67 analysis. Treatment decision is individualized based on 4 wk Ki67 and modified PEPI score. Pts with Ki67 > 10% at 4 wk are switched to chemotherapy. Pts with a modified PEPI score of 0 are recommended not to receive chemotherapy, but continue the assigned ET for 1.5 years followed by 3 years of A. This trial is currently accruing pts through CTSU. This research is supported in part by NCI BIQSFP, and grants from Breast Cancer Research Foundation, Genentech, and the Investigator-Sponsored Study Program of AstraZeneca. The Clinical Trials.gov Identifier: NCT01953588. Citation Format: Cynthia X Ma, Vera Suman, A Marilyn Leitch, Souzan Sanati, Katherine DeSchryver, Gary W Unzeitig, Paul Haluska, Mark Watson, Olwen Hahn, Jo Anne Zujewski, Kelly Hunt, Eric P Winer, Cliff A Hudis, Matthew J Ellis. Alliance A011106: ALTernate approaches for clinical stage II or III Estrogen Receptor positive breast cancer NeoAdjuvant TrEatment (ALTERNATE) in postmenopausal women: A phase III study [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 OT2-1-04.

Abstract Background: Literature addressing metformin exposure post diagnosis of breast cancer hints at a potential protective association on mortality outcomes, although findings have been inconclusive. In this research, we contribute to this body of evidence by using robust clinical indicators to focus on subgroups of breast cancer patients that might be most appropriate for potential metformin treatment. Methods: Robust breast cancer staging, treatment, and medication exposure attributes were compiled from Mayo Clinic Electronic Health Records and Breast Cancer Registry using a combination of structured queries and natural language processing of clinical notes. A cohort of female Breast Cancer Registry patients having type II diabetes mellitus (T2DM) at breast cancer diagnosis with a median follow-up period of 79.0 months after breast cancer diagnosis was identified (N=350). Univariate and multivariate cox proportional hazard regression analysis were used to model characteristics of BMI at diagnosis, age at diagnosis, metformin, insulin, thiazolidinedione, and sulfonylurea exposure after diagnosis, cancer grade, cancer stage, chemotherapy, hormone therapy, radiotherapy, lumpectomy, and mastectomy. Patients presenting with metastatic breast cancer at diagnosis, receiving immunotherapy for breast cancer treatment, and concurrent metformin and insulin exposure for T2DM treatments were excluded from the analysis cohort. Results: Univariate analysis independently identified metformin exposure (HR=0.243,p=0.0016), insulin exposure (HR=3.481,p=0.0210), age at breast cancer diagnosis (HR=1.075,p=0.0001), and targeted radiotherapy (HR=0.337,p=0.0082) as having a significant association with all-cause mortality. The multivariate model of metformin exposure (HR=0.274,p=0.0123), insulin exposure (HR=2.502,p=0.1160), age at breast cancer diagnosis (HR=1.043,p=0.0480), and targeted radiotherapy (HR=0.303,p=0.0044) on all-cause mortality demonstrated significant associations for all variables (Wald Chi-Square=25.2916,p<0.0001). A parallel multivariate model demonstrated metformin exposure (HR=0.101,p=0.0323), insulin exposure (HR=5.241,p=0.0265), and targeted radiotherapy (HR=0.292,p=0.0520) as having significant associations with breast cancer-specific mortality. Discussion: These findings suggest a protective association for metformin and a potential detrimental association for insulin therapy on all-cause and breast cancer-specific mortality amongst non-metastatic breast cancer patients with T2DM. The findings presented include robust clinical indicators for BMI, stage, and grade at diagnosis, post-diagnosis diabetes medication exposure, and endpoints of all cause and breast cancer specific mortality that have not been available in larger population studies. Our findings have potential pharmacogenetic implications for inhibition of localized breast cancer cell growth by targeting downstream components of the adenosine monophosphate-activated protein kinase pathway, the insulin/insulin-like growth factor-1 signaling pathway, and directly and indirectly via additional metabolic pathways with specific drug therapy combinations. Citation Format: Matthew K. Breitenstein, Leiwei Wang, Richard M. Weinshilboum, Jyotishman Pathak. Metformin exposure on survival in localized breast cancer patients with type II diabetes mellitus using electronic health records. [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 LB-278. doi:10.1158/1538-7445.AM2014-LB-278

Abstract Background: Specific germline alterations within the TERT, EGFR, CCDC26, CDKN2A/B, PHLDB1, TP53 and RTEL1 regions are associated with development of glioma. While some of these germline variants are associated with all gliomas (e.g. rs2736100 in TERT), others are associated with a specific morphologic and/or molecular subtype. For example, the RTEL1 region variants are associated with primary glioblastoma and rs55705857 in CCDC26 is associated with 1p/19q co-deleted oligodendrogliomas and with IDH mutant astrocytic gliomas. We hypothesized that germline variants in these regions will be associated with other molecular subtypes. The Cancer Genome Atlas (TCGA) and other groups have described molecular subtypes of glioma based on acquired somatic mutation patterns. Herein, we grouped glioma patients into mutation-based molecular subgroups based on three molecular alterations and determined if germline polymorphisms are associated with these mutation-based molecular subtypes. Methods: Five molecular subtypes were defined based on combinations of the following molecular alterations: TERT promoter mutation (TERTmut vs. TERTwt), IDH1/2 mutation (IDH mut vs. IDH wt) and 1p/19q co-deletion (1p19qcodel vs. 1p19q noncodel). Germline single nucleotide polymorphisms (SNPs) were evaluated by custom Illumina array analysis of blood-derived DNA and 1K genome imputation. Results: One hundred ninety-nine gliomas (24 oligodendrogliomas, 59 mixed oligoastrocytomas, 41 grade 2-3 astrocytomas and 75 glioblastomas) had both SNP data and mutation data available in order to assign them into the five molecular subgroups. The prevalence of each of the molecular subtypes was as follows: TERTmut/IDHmut/1p19qcodel (20%), TERTmut/IDHmut/1p19qnoncodel (5%), TERTmut/IDHwt/1p19qnoncodel (32%), TERTwt/IDHmut/1p19qnondel (35%) and TERTwt/IDHwt/1p19qnoncodel (8%). The TERT SNP (rs2736100) was protective for TERTmut/IDHmut/1p19qnoncodel and TERTwt/IDHmut/1p19qnoncodel gliomas. The CCDC26 SNP (rs55705857) was strongly associated with the risk of developing TERTmut/IDHmut/1p19qcodel and TERTwt/IDHmut/1p19qnoncodel gliomas. The TP53 SNP (rs7837822) was strongly associated with risk of developing TERTmut/IDHmut/1p19qnoncodel and TERTwt/IDHmut/1p19qnoncodel gliomas. Interestingly, while one RTEL1 region SNP (rs6062297) was strongly associated with glioma risk, RTEL1 SNPs rs6010620 and rs2297440 were protective for the development of TERTmut/IDHwt/1p19qnoncodel gliomas. We are currently in the process of validating these results using the TCGA glioblastoma and low grade glioma data. Conclusions: Glioma patients can be meaningfully classified according to their acquired mutation subtype. Importantly, our results suggest that there are significant associations between germline polymorphisms and mutation-based glioma molecular subtypes. Citation Format: Jeanette E. Eckel-Passow, Thomas M. Kollmeyer, Gobinda Sarkar, Anisha Chada, Paul A. Decker, Matthew L. Kosel, Alissa A. Caron, Hugues Sicotte, Kannabiran Nandakumar, Naresh Prodduturi, Brian P. O'Neill, Daniel H. Lachance, Robert B. Jenkins. The association of glioma germline risk SNPs with mutation-based molecular subgroups. [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 4714. doi:10.1158/1538-7445.AM2014-4714

Abstract Oncolytic replication competent viruses are increasingly being tested in clinical trials. Their optimal use would be greatly facilitated by technologies that enable repeated and quantitative estimation of the location and population size of the virus as it propagates within the tumor. To address this, we have generated two replication competent measles viruses (MV) that express the thyroidal sodium iodide symporter (NIS) in injected cells. One virus, MV-NIS is in Phase 1 clinical trials and kills cells by formation of syncytia. The second virus, MV-I98A-NIS has a mutation in the MV hemagglutinin protein that prevents syncytium formation and kills cells by lysis. Cells infected with MV-I98A-NIS remain viable for longer compared to MV-NIS and are expected to express higher concentrations of NIS, facilitating in vivo imaging. BxPC-3 human pancreatic carcinoma cells were implanted in the flank of nude mice. Subsequently, the mice were injected with Opti-MEM (control), MV-NIS or MV-I98A-NIS (1x107 TCID50/ml) via the tail vein. On days 3, 5, 8, 10, 12, 15, 17 and 19 after virus injection, mice from the control, and virus injected groups were imaged with SPECT/CT (U-SPECT II) 1 hour after injection of 99mTc. Immediately afterwards, the mice were euthanized, the tumors excised, weighed and isotope activity measured. The tumors were divided into parts for histologic analysis and RNA extraction. NIS gene expression was determined by Q-RT-PCR and immunohistochemistry, while viral genome copy number was determined by Q-RT-PCR for the nucleoprotein (N). Image analysis using ROI was performed using AMIDE with background correction across all imaging planes. There was no correlation between tumor mass (volume) and isotope uptake (R2=0.0001 and 0.0051 for MV-NIS and MV-I98A-Nis respectively) suggesting that isotope uptake was strictly linked to virus infection. There was a strong, linear correlation between the levels of virus dependent NIS expression and isotope activity within the tumor (R2=0.79 and 0.93 for MV-NIS and MV-I98A-NIS respectively). Tumors infected with MV-I98A-NIS had a higher concentration of isotope compared with MV-NIS (p<0.004) and a higher correlation coefficient of NIS isotope uptake versus NIS expression (14.1 mCi/NIS copies/ng RNA versus 11.5, p=0.003), compatible with the observation that tumor cells infected with MV-I98A-NIS remain viable for longer compared to MV-NIS. Activity within tumors increased as a function of time, compatible with ongoing virus replication and spread within the tumors. Correlation of imaging studies with NIS expression and viral genome copy number is ongoing. Our preliminary studies suggest that in vivo imaging can be used to accurately determine the size of the oncolytic virus population within a tumor as a function of time. These observations will be used to understand the dynamics of virus spread within tumors and optimize therapy. Citation Format: Mi-Yeon Jung, Matthew K. Ennis, Chetan P. Offord, David Dingli. Quantitative in vivo imaging of oncolytic virus replication. [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 4947. doi:10.1158/1538-7445.AM2014-4947

Abstract Background: Breast cancer recurrence has been shown to differ based upon CYP2D6 genotype and endoxifen (Endx) exposure following treatment with tamoxifen (TAM) in the adjuvant setting. The average Endx Css is 29 nM (range, 2-80 nM) in TAM treated patients at a dose of 20 mg/day. Administration of Endx itself to patients is predicted to provide adequate, consistent, active drug levels in all treated patients, resulting in clinical benefit. As part of two phase 1 trials of oral Endx to determine the safety, tolerability, and MTD, we characterized the pharmacokinetics and in vivo metabolism of Endx. Methods: Patients were given escalating daily oral doses of Endx (28 day cycle) over the dose range of 20 - 160 mg/day in Phase I trials at the Mayo Clinic and NCI. Pharmacokinetics sampling was performed on days 1, 7, 14 and 28, and prior to subsequent cycles. Endx plasma concentrations and metabolite profiles were determined by HPLC and LC/MS/MS. Results: 44 patients with ECOG PS 0-1 have been enrolled to date encompassing 8 dose levels in the Mayo (25 women with AI refractory MBC; median age 58 yrs, range 41-83 yrs) and NCI (19 women with ovary (9), breast (4), desmoid (2), fallopian tube (2), endometrial cancer (2); median age 64 yrs, range 43-75 yrs) studies. Day 1 Endx peak concentrations (Cmax) were reached 4h after the Endx oral dose and mean values of Cmax, C24h, and AUC0-24h increased in proportion to dose. Css was achieved on day 7 and 3.5-fold accumulation (t1/2= 50.5 h) was observed on day 28. At the starting dose ( 20 mg/day) and highest dose level (160 mg/day), Endx Css values of 146 ng/ml (390 nM) and 1950 ng/ml (5200 nM), respectively, were achieved and maintained throughout the 28-day treatment. Endx Css values remained unchanged following continuous dosing for 8-10 months. The mean apparent steady-state clearance was 6.2 L/h. We also characterized the Endx metabolite profile in patient plasma and urine. Metabolites detected in plasma include nor-Endx, N-hydroxy-Endx, Endx-catechol, methoxy-Endx catechol, and Endx-glucuronide, and appear in amounts much lower compared to Endx. Like the parent drug, metabolites accumulated in plasma over the 28-day cycle. Characterization of the pharmacokinetics of Nor-Endx, a putative aromatase inhibitor, is ongoing and will be presented. Conclusion: In these ongoing Phase I studies, daily administration of Endx is well tolerated with Css consistently above those obtained following administration of standard dose tamoxifen. In the Mayo study, expansion at 20 and 100 mg/day has commenced to perform translational studies and further characterize Endx PK. In the NCI study, dose escalation continues to establish the maximum tolerated dose. Supported in part by R01CA 133049, U01 CA69912, P30CA 15083, P50CA 116201 and NCI Contracts CM52206 and HHSN261201100014C. Citation Format: Joel M. Reid, Matthew P. Goetz, Shivaani Kumar, Renee M. McGovern, Sarah A. Buhrow, Stephanie L. Safgren, Vera J. Suman, Travis J. Docktor, Charles Erlichman, Howard Streicher, James H. Doroshow, Jerry Collins, Matthew M. Ames. Pharmacokinetics and in vivo metabolism of Z-endoxifen: Results from two phase I studies in women with ER+ breast cancer, gynecologic malignancies and desmoids. [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 4631. doi:10.1158/1538-7445.AM2014-4631

Abstract Despite remarkable therapeutic advances in malignant melanoma, an incomplete understanding of melanoma's extraordinary genetic diversity, complex disease course and ability to resist treatment continues to impede rational, curative clinical intervention. This is particularly true for the understudied “dark matter” of the melanoma genome, i.e. cases that lack mutations in the three most commonly-mutated melanoma genes (BRAF, NRAS, NF1) and that display extensive mutational heterogeneity. Clearly a pressing need exists for transformative approaches to melanoma medicine. We have therefore broadened our traditional focus on melanoma in human patients to include canine melanoma as a model of human disease. Given canine melanoma's clinicopathological resemblance to human non-cutaneous triple-negative subtypes, study of this disease in each species may inform the other. Further, the accelerated clinical course of canine melanoma and flexibility in veterinary clinical trial design may allow for evaluation of novel treatment designs that would not be possible in human cancer trials. Thus, we have undertaken a first-in-dog genomic characterization study of canine melanomas from a cohort of 37 dogs to further explore the landscape of this comparative model. This analysis combines comprehensive genomics (whole genome, whole genome long-insert, RNA sequencing, and array comparative genomic hybridization) in 7 matched canine melanoma/normal tissues with targeted analysis in an additional 27 tumors and 3 cell lines. These canine tumors display striking patterns of mutation and subtype heterogeneity resembling that of their non-cutaneous human counterparts with the majority being BRAF, NRAS, and NF1 wild type and lacking recurrent single nucleotide variants. Despite heterogeneity at the single nucleotide level, shared patterns of structural variation and gene expression exist and these patterns suggest core pathways that may define therapeutic vulnerabilities in these disease subtypes. These data provide the genomic framework for further clinical pursuit of melanoma in the canine model as a paradigm for drug development. Citation Format: William P. Hendricks, Victoria Zismann, Berry Button, Christophe Legendre, Waibhav Tembe, Holly Yin, Michael Bittner, Donald Berry, Matthew Huentelman, Chand Khanna, Patricia LoRusso, Matthew Breen, Aleksandar Sekulic, Jeffrey Trent. The genomic landscape of canine melanoma reveals broad mutational heterogeneity and recurrent patterns of structural variation. [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 3417. doi:10.1158/1538-7445.AM2014-3417

Abstract Introduction: We recently reported the percentage of mammographic density (MD) to be a breast cancer risk factor across tumor characteristics and age groups. Yet, we noted stronger associations for tumors of large size and positive lymph nodes across all ages, and ER-negative status among women ages <55 years, suggesting high MD may play an important role in tumor aggressiveness, especially in younger women. We extend this initial study to investigate whether these associations with aggressive disease are due to the underlying associations of absolute dense or non-dense area, or both, with breast cancer risk. Methods: Data were pooled from six studies including 3517 women with invasive breast cancer and 8558 without. Dense area and non-dense area were assessed from digitized film-screen mammograms using a computer-assisted threshold technique. We standardized dense and non-dense area measurements made within each study and categorized into quartiles based on the control distribution for pooled analyses. We used polytomous logistic regression to calculate breast cancer odds according to tumor type, histopathological characteristics, and receptor (ER, PR) status by age (<55, 55-64, and ≥65 years), adjusting for continuous age, body mass index, and study site. Results: Absolute dense area was associated with increased breast cancer risk [odds ratios (ORs) Q1 vs Q2: 0.67, Q3 vs Q2: 1.25, Q4 vs Q2: 1.62] and non-dense area was associated with decreased breast cancer risk (ORs: Q1 vs Q2: 1.44, Q3 vs Q2: 0.89, Q4 vs Q2: 0.71) overall and across all age groups. Positive associations for absolute dense area were observed across all invasive tumor characteristics. Stronger associations were noted for larger tumors across all ages (p-trend <0.01). Among women <55 years, stronger associations were observed for ER+ vs ER- [p-heterogeneity (het) = 0.02] and PR+ vs PR- tumors (p-het = 0.02). Non-dense area was inversely associated with all tumor characteristics evaluated except for tumors <1.1 cm, for which no association was present. The inverse association was stronger for larger tumors, particularly for women <55 years (p-trend <0.01). Also among women <55 years, a stronger inverse association with non-dense area was observed for ER- vs. ER+ tumors (p-het = 0.02). Conclusion: These results suggest the strong association we previously observed of high percent MD and ER-negative disease in women <55 years could be explained by the low amount of non-dense area in these women. Further research is warranted to clarify the possible differential associations of absolute dense and non-dense area on breast cancer risk according to tumor characteristics. Citation Format: Kimberly A. Bertrand, Christopher G. Scott, Rulla M. Tamimi, Matthew R. Jensen, V. Shane Pankratz, Aaron Norman, John Shepherd, Yunn-Yi Chen, Karla Kerlikowske, Celine M. Vachon. Dense and non-dense mammographic area and risk of breast cancer by age and tumor characteristics. [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 3279. doi:10.1158/1538-7445.AM2014-3279

Abstract Ovarian cancer is the most common and most lethal gynecologic malignancy. Despite clear histologic and molecular differences between disease subtypes, all patients receive cytotoxic chemotherapy and survival has not improved significantly for several decades. Identifying avenues for targeted therapy is critical to improving clinical outcomes. Given the vast heterogeneity of ovarian cancer, therapeutic strategies will vary based on subtype and specific biomarkers. Estrogen receptor-alpha (ER) is expressed in ∼70% of serous ovarian tumors and epidemiologic evidence indicates estrogen contributes to the disease etiology. Further, clinical data suggest that a subset of patients with serous carcinoma benefit from endocrine therapy. However, the full potential of endocrine therapy in ovarian cancer has been understudied. We hypothesize that a subset of serous ovarian tumors are dependent upon estrogen and that expression of ER target genes will identify patients who can be successfully treated with endocrine therapy. We characterized response to estradiol (E2) in four ER+ serous ovarian cancer cell lines, focusing on cell proliferation, survival, and gene expression. Proliferation was evaluated in 2-D and in a 3-D matrigel system. Survival was assayed in low-attachment conditions. We also evaluated response to anti-estrogens 4-hydroxytamoxifen (4OHT) and fulvestrant (ICI). Expression of canonical ER targets (e.g. GREB1, IGFBP3) was measured by qPCR. Gene expression microarrays after E2 treatment were used to identify genome-wide effects of ER. Studies of endocrine response in vivo are ongoing in patient-derived xenograft models. E2 promotes growth of PEO1 and PEO4 cells in 2-D and 3-D culture, with PEO4 cells exhibiting greater E2 dependence. Preliminary results indicate that E2 also promotes survival in low-attachment conditions. Growth and survival are both decreased by treatment with fulvestrant or 4-hydroxytamoxifen. Conversely, OVCA432 and OVSAHO cells do not respond to treatment with ER ligands. Microarrays identified E2-regulated genes in PEO1 and PEO4 cells that may be utilized as biomarkers of ER activity. Several of these ER targets are differentially expressed between E2-responsive and E2-independent cell lines including DEPTOR, GREB1, GFRA2, and EPHB3. We are currently overlapping our array results with publicly available datasets to develop a gene signature of E2 response, which we will use to profile ER signaling in clinical specimens and patient derived xenografts. Our results suggest that a subset of serous ovarian cancers are endocrine responsive. These studies will determine if expression of specific ER targets correlates with endocrine response and thus if they can be harnessed to predict clinical response to endocrine therapy. Citation Format: Courtney L. Andersen, Matthew J. Sikora, Soumya Luthra, Uma Chandran, Paul Haluska, Steffi Oesterreich. Utilizing ER target genes as biomarkers of endocrine response in serous ovarian carcinoma. [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 2103. doi:10.1158/1538-7445.AM2014-2103