Anderson, William F.

Abstract Purpose: Ovarian cancer is a heterogeneous disease that can be divided into multiple subtypes with variable etiology, pathogenesis, and prognosis. We analyzed DNA methylation profiling data to identify biologic subgroups of ovarian cancer and study their relationship with histologic subtypes, copy number variation, RNA expression data, and outcomes. Experimental Design: A total of 162 paraffin-embedded ovarian epithelial tumor tissues, including the five major epithelial ovarian tumor subtypes (high- and low-grade serous, endometrioid, mucinous, and clear cell) and tumors of low malignant potential were selected from two different sources: The Polish Ovarian Cancer study, and the Surveillance, Epidemiology, and End Results Residual Tissue Repository (SEER RTR). Analyses were restricted to Caucasian women. Methylation profiling was conducted using the Illumina 450K methylation array. For 45 tumors array copy number data were available. NanoString gene expression data for 39 genes were available for 61 high-grade serous carcinomas (HGSC). Results: Consensus nonnegative matrix factorization clustering of the 1,000 most variable CpG sites showed four major clusters among all epithelial ovarian cancers. We observed statistically significant differences in survival (log-rank test, P = 9.1 × 10−7) and genomic instability across these clusters. Within HGSC, clustering showed three subgroups with survival differences (log-rank test, P = 0.002). Comparing models with and without methylation subgroups in addition to previously identified gene expression subtypes suggested that the methylation subgroups added significant survival information (P = 0.007). Conclusions: DNA methylation profiling of ovarian cancer identified novel molecular subgroups that had significant survival difference and provided insights into the molecular underpinnings of ovarian cancer. See related commentary by Ishak et al., p. 5729

Abstract Background: Estrogen receptor (ER) status in breast cancer is strongly associated with etiologic factors, prognosis and treatment response. Data suggest that population-based incidence rates of ER-positive (ER+) tumors are increasing and ER-negative (ER-) cancers have fallen over time in the United States (US), Denmark and Scotland. Whether these trends are consistent in other populations with different etiologic exposures and across ER±/HER2± subtypes is unknown. We, therefore, analyzed breast cancer secular trends in Ireland by ER expression; and for the first time, by joint expression of ER±/HER2±, a well-established clinical marker of uncertain etiological significance. Methods: This study included invasive breast cancers (n=24,845; 2004-2013) among women aged 20-84 years within the population-based National Cancer Registry of Ireland (97% coverage). The general population at risk (n=10,401,986) was obtained from the Irish Central Statistics Office. Using a validated approach to account for missing ER/HER2-status, we assessed ER± and ER±/HER2± secular trends with age-standardized incidence rates (ASR) and estimated annual percentage change (EAPC) with 95% confidence intervals (95%CI). Results: Over the 10-year follow-up period, 19,264 ER+ and 4,161 ER- breast cancers were diagnosed (1,420 were ER-unknown). ASRs increased significantly for ER+ (EAPC: 2.20%/year (95%CI: 0.97, 3.45%/year)) and decreased significantly for ER- cancers (EAPC: -3.43%/year (95%CI: -5.05, -1.78%/year)). The ER-specific trends were qualitatively similar among three age groups (<50, 50-64 and ≥65 years). With further stratification by HER2± expression, ER+/HER2- cancers rose (EAPC: 2.87%/year (95%CI: 1.33, 4.44%/year)), ER+/HER2+ cancers were statistically flat, while ER-/HER± cancers significantly declined. Conclusion: Secular trends for ER± cancers in Ireland were similar to those previously observed in the US and Denmark. Further, trends for ER/HER2 followed those for ER, although rates were constant for ER+/HER+ tumors. The divergence of cancer incidence patterns by ER among independent populations over time could reflect comparable changes in risk factor exposures with dual or opposite effects for risk of ER+ and ER- cancers (e.g., obesity, age at first birth/parity). Additionally, although HER2 is a well-established clinical predictive and prognostic marker for breast cancer outcome, it did not appear to substantively impact breast cancer incidence trends. Citation Format: Maeve Mullooly, Jeanne Murphy, Gretchen L. Gierach, Brittny Davis, Paul Walsh, Sandra Deady, Thomas I. Barron, Mark E. Sherman, Philip S. Rosenberg, William F. Anderson. Estrogen receptor positive and negative breast cancer secular trends in Ireland (2004-2013) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 257. doi:10.1158/1538-7445.AM2017-257