Pearce, Celeste Leigh

Abstract Background: Despite a large body of literature evaluating the association between recreational physical activity and epithelial ovarian cancer (EOC) risk, the extant evidence is inconclusive, and little is known about the independent association between recreational physical inactivity and EOC risk. We conducted a pooled analysis of nine studies from the Ovarian Cancer Association Consortium to investigate the association between chronic recreational physical inactivity and EOC risk. Methods: In accordance with the 2008 Physical Activity Guidelines for Americans, women reporting no regular, weekly recreational physical activity were classified as inactive. Multivariable logistic regression was utilized to estimate the ORs and 95% confidence intervals (CI) for the association between inactivity and EOC risk overall and by subgroups based upon histotype, menopausal status, race, and body mass index. Results: The current analysis included data from 8,309 EOC patients and 12,612 controls. We observed a significant positive association between inactivity and EOC risk (OR = 1.34; 95% CI, 1.14–1.57), and similar associations were observed for each histotype. Conclusions: In this large pooled analysis examining the association between recreational physical inactivity and EOC risk, we observed consistent evidence of an association between chronic inactivity and all EOC histotypes. Impact: These data add to the growing body of evidence suggesting that inactivity is an independent risk factor for cancer. If the apparent association between inactivity and EOC risk is substantiated, additional work via targeted interventions should be pursued to characterize the dose of activity required to mitigate the risk of this highly fatal disease. Cancer Epidemiol Biomarkers Prev; 25(7); 1114–24. ©2016 AACR.

Abstract Background Genome-wide association studies (GWAS) previously identified 8 new risk loci for all subtypes of epithelial ovarian carcinoma (EOC) and one specific to invasive serous EOC. One locus, at 2q31, was also associated with invasive mucinous EOC (mEOC) at P=7.3 x 10-7 (Nat Genet 2010:874). Here, we report new risk loci for mEOC, which is thought to develop from a borderline mucinous tumor. These loci may provide clues to the molecular basis of the disease. Methods We used genotype data from 4 GWAS of EOC and from multiple case-control studies in the Ovarian Cancer Association Consortium that had been genotyped using the iCOGS custom SNP panel (210k SNPs) developed for the Collaborative Oncological Gene-environment Study. We imputed genotypes of common variation across the genome using the 1000 Genomes Project reference panel and tested for association using log-additive unconditional regression models. Results Genotypes were available for 1,643 combined invasive and borderline mEOC and for 1,002 invasive-only mEOC of European ancestry. Three loci in new regions, and one locus in a previously published region, with minor allele frequency (MAF) > 1% and P ≤ 10-7 were found. The imputed SNP rs72831838 (imputation r2=0.67, MAF=0.15) is located at 2q13 in an intron of the PAX8 (paired box 8) gene (all mEOC OR=1.35, P=4.2 x 10-8 and invasive-only OR=1.43, P=9.6 x 10-8). PAX8 is a transcription factor and may be a Müllerian lineage marker that distinguishes carcinomas of gynecologic origin from other sites. The imputed variant at chr19:39745695 (imputation r2=0.61, MAF=0.32) is an insertion/deletion polymorphism located at 19q13.2 and falls within the MSRB1P1 (methionine sulfoxide reductase B1 pseudogene 1). This locus was associated with decreased risk (all mEOC OR=0.74, P = 2.1 x 10-9 and invasive-only OR=0.79, P = 8.1 x 10-5) and is enriched with the H3K27Ac histone mark that identifies active enhancers of gene expression. The imputed SNP rs6425050 (imputation r2=0.45, MAF=0.19) is located at 1q25 (all mEOC OR=1.38, P=4.7 x 10-8 and invasive-only OR=1.41, P=1.6x10-6). This SNP is intronic to PLA2G4A (phospholipase A2, group IVA), which encodes an enzyme that hydrolyzes membrane phospholipids for eicosanoid metabolism and signaling. None of these loci were associated with other EOC histological subtypes at P ≤ 10-7. The genotyped SNP, rs711830 (MAF=0.32), is located at 2q31.1 in the 3′ region of the HOXD3 homeobox gene (all mEOC OR=1.30, P=7.5 x 10-12 and invasive-only OR=1.26, P=7.8 x 10-7). This SNP is highly correlated (r2=0.99) with rs2072590, which is located 5.3kb upstream and previously reported by us to be associated with mEOC and invasive serous EOC (Nat Genet 2010:874). The HOXD3 locus is highly conserved and may also be a marker of Müllerian cell type origin. Conclusions The 3 new loci for mEOC require confirmation by genotyping. Fine mapping and functional analysis of all loci is needed in order to determine their likely target genes. Citation Format: Linda E. Kelemen, Jonathan Tyrer, Catherine M. Phelan, Susan J. Ramus, Andrew Berchuck, Simon A. Gayther, Ellen L. Goode, Celeste L. Pearce, Joellen M. Schildkraut, Georiga Chenevix-Trench, Alvaro N. Monteiro, Marc T. Goodman, Thomas A. Sellers, Paul PD Pharoah. GWAS identifies risk variants for mucinous 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 3283. doi:10.1158/1538-7445.AM2014-3283

AbstractOver 22,000 cases of ovarian cancer were diagnosed in 2007 in the United States, but only a fraction of them can be attributed to mutations in highly penetrant genes such as BRCA1. To determine whether low-penetrance genetic variants contribute to ovarian cancer risk, we genotyped 1,536 single nucleotide polymorphisms (SNP) in several candidate gene pathways in 848 epithelial ovarian cancer cases and 798 controls in the North Carolina Ovarian Cancer Study (NCO) using a customized Illumina array. The inflammation gene interleukin-18 (IL18) showed the strongest evidence for association with epithelial ovarian cancer in a gene-by-gene analysis (P = 0.002) with a <25% chance of being a false-positive finding (q value = 0.240). Using a multivariate model search algorithm over 11 IL18 tagging SNPs, we found that the association was best modeled by rs1834481. Further, this SNP uniquely tagged a significantly associated IL18 haplotype and there was an increased risk of epithelial ovarian cancer per rs1834481 allele (odds ratio, 1.24; 95% confidence interval, 1.06-1.45). In a replication stage, 12 independent studies from the Ovarian Cancer Association Consortium (OCAC) genotyped rs1834481 in an additional 5,877 cases and 7,791 controls. The fixed effects estimate per rs1834481 allele was null (odds ratio, 0.99; 95% confidence interval, 0.94-1.05) when data from the 12 OCAC studies were combined. The effect estimate remained unchanged with the addition of the initial North Carolina Ovarian Cancer Study data. This analysis shows the importance of consortia, like the OCAC, in either confirming or refuting the validity of putative findings in studies with smaller sample sizes. (Cancer Epidemiol Biomarkers Prev 2008;17(12):3567–72)