Malcolm C. Pike

Development and Validation of the Gene Expression Predictor of High-grade Serous Ovarian Carcinoma Molecular SubTYPE (PrOTYPE)

Abstract Purpose: Gene expression–based molecular subtypes of high-grade serous tubo-ovarian cancer (HGSOC), demonstrated across multiple studies, may provide improved stratification for molecularly targeted trials. However, evaluation of clinical utility has been hindered by nonstandardized methods, which are not applicable in a clinical setting. We sought to generate a clinical grade minimal gene set assay for classification of individual tumor specimens into HGSOC subtypes and confirm previously reported subtype-associated features. Experimental Design: Adopting two independent approaches, we derived and internally validated algorithms for subtype prediction using published gene expression data from 1,650 tumors. We applied resulting models to NanoString data on 3,829 HGSOCs from the Ovarian Tumor Tissue Analysis consortium. We further developed, confirmed, and validated a reduced, minimal gene set predictor, with methods suitable for a single-patient setting. Results: Gene expression data were used to derive the predictor of high-grade serous ovarian carcinoma molecular subtype (PrOTYPE) assay. We established a de facto standard as a consensus of two parallel approaches. PrOTYPE subtypes are significantly associated with age, stage, residual disease, tumor-infiltrating lymphocytes, and outcome. The locked-down clinical grade PrOTYPE test includes a model with 55 genes that predicted gene expression subtype with >95% accuracy that was maintained in all analytic and biological validations. Conclusions: We validated the PrOTYPE assay following the Institute of Medicine guidelines for the development of omics-based tests. This fully defined and locked-down clinical grade assay will enable trial design with molecular subtype stratification and allow for objective assessment of the predictive value of HGSOC molecular subtypes in precision medicine applications. See related commentary by McMullen et al., p. 5271

Identification of novel epithelial ovarian cancer loci in women of African ancestry

Women of African ancestry have lower incidence of epithelial ovarian cancer (EOC) yet worse survival compared to women of European ancestry. We conducted a genome‐wide association study in African ancestry women with 755 EOC cases, including 537 high‐grade serous ovarian carcinomas (HGSOC) and 1,235 controls. We identified four novel loci with suggestive evidence of association with EOC (p < 1 × 10−6), including rs4525119 (intronic to AKR1C3), rs7643459 (intronic to LOC101927394), rs4286604 (12 kb 3′ of UGT2A2) and rs142091544 (5 kb 5′ of WWC1). For HGSOC, we identified six loci with suggestive evidence of association including rs37792 (132 kb 5′ of follistatin [FST]), rs57403204 (81 kb 3′ of MAGEC1), rs79079890 (LOC105376360 intronic), rs66459581 (5 kb 5′ of PRPSAP1), rs116046250 (GABRG3 intronic) and rs192876988 (32 kb 3′ of GK2). Among the identified variants, two are near genes known to regulate hormones and diseases of the ovary (AKR1C3 and FST), and two are linked to cancer (AKR1C3 and MAGEC1). In follow‐up studies of the 10 identified variants, the GK2 region SNP, rs192876988, showed an inverse association with EOC in European ancestry women (p = 0.002), increased risk of ER positive breast cancer in African ancestry women (p = 0.027) and decreased expression of GK2 in HGSOC tissue from African ancestry women (p = 0.004). A European ancestry‐derived polygenic risk score showed positive associations with EOC and HGSOC in women of African ancestry suggesting shared genetic architecture. Our investigation presents evidence of variants for EOC shared among European and African ancestry women and identifies novel EOC risk loci in women of African ancestry.

High Prediagnosis Inflammation-Related Risk Score Associated with Decreased Ovarian Cancer Survival

Abstract Background: There is suggestive evidence that inflammation is related to ovarian cancer survival. However, more research is needed to identify inflammation-related factors that are associated with ovarian cancer survival and to determine their combined effects. Methods: This analysis used pooled data on 8,147 women with invasive epithelial ovarian cancer from the Ovarian Cancer Association Consortium. The prediagnosis inflammation-related exposures of interest included alcohol use; aspirin use; other nonsteroidal anti-inflammatory drug use; body mass index; environmental tobacco smoke exposure; history of pelvic inflammatory disease, polycystic ovarian syndrome, and endometriosis; menopausal hormone therapy use; physical inactivity; smoking status; and talc use. Using Cox proportional hazards models, the relationship between each exposure and survival was assessed in 50% of the data. A weighted inflammation-related risk score (IRRS) was developed, and its association with survival was assessed using Cox proportional hazards models in the remaining 50% of the data. Results: There was a statistically significant trend of increasing risk of death per quartile of the IRRS [HR = 1.09; 95% confidence interval (CI), 1.03–1.14]. Women in the upper quartile of the IRRS had a 31% higher death rate compared with the lowest quartile (95% CI, 1.11–1.54). Conclusions: A higher prediagnosis IRRS was associated with an increased mortality risk after an ovarian cancer diagnosis. Further investigation is warranted to evaluate whether postdiagnosis exposures are also associated with survival. Impact: Given that pre- and postdiagnosis exposures are often correlated and many are modifiable, our study results can ultimately motivate the development of behavioral recommendations to enhance survival among patients with ovarian cancer.

Depot-Medroxyprogesterone Acetate Use Is Associated with Decreased Risk of Ovarian Cancer: The Mounting Evidence of a Protective Role of Progestins

AbstractBackground:Combined oral contraceptive use is associated with a decreased risk of invasive epithelial ovarian cancer (ovarian cancer). There is suggestive evidence of an inverse association between progestin-only contraceptive use and ovarian cancer risk, but previous studies have been underpowered.Methods:The current study used primary data from 7,977 women with ovarian cancer and 11,820 control women in seven case–control studies from the Ovarian Cancer Association Consortium to evaluate the association between use of depot-medroxyprogesterone acetate (DMPA), an injectable progestin-only contraceptive, and ovarian cancer risk. Logistic models were fit to determine the association between ever use of DMPA and ovarian cancer risk overall and by histotype. A systematic review of the association between DMPA use and ovarian cancer risk was conducted.Results:Ever use of DMPA was associated with a 35% decreased risk of ovarian cancer overall (OR, 0.65; 95% confidence interval, 0.50–0.85). There was a statistically significant trend of decreasing risk with increasing duration of use (Ptrend < 0.001). The systematic review yielded six studies, four of which showed an inverse association and two showed increased risk.Conclusions:DMPA use appears to be associated with a decreased risk of ovarian cancer in a duration-dependent manner based on the preponderance of evidence. Further study of the mechanism through which DMPA use is associated with ovarian cancer is warranted.Impact:The results of this study are of particular interest given the rise in popularity of progestin-releasing intrauterine devices that have a substantially lower progestin dose than that in DMPA, but may have a stronger local effect.

Reproductive Factors Do Not Influence Survival with Ovarian Cancer

Abstract Background: Previous studies on the association between reproductive factors and ovarian cancer survival are equivocal, possibly due to small sample sizes. Methods: Using data on 11,175 people diagnosed with primary invasive epithelial ovarian, fallopian tube, or primary peritoneal cancer (ovarian cancer) from 16 studies in the Ovarian Cancer Association Consortium (OCAC), we examined the associations between survival and age at menarche, combined oral contraceptive use, parity, breastfeeding, age at last pregnancy, and menopausal status using Cox proportional hazard models. The models were adjusted for age at diagnosis, race/ethnicity, education level, and OCAC study and stratified on stage and histotype. Results: During the mean follow-up of 6.34 years (SD = 4.80), 6,418 patients passed away (57.4%). There was no evidence of associations between the reproductive factors and survival among patients with ovarian cancer overall or by histotype. Conclusions: This study found no association between reproductive factors and survival after an ovarian cancer diagnosis. Impact: Reproductive factors are well-established risk factors for ovarian cancer, but they are not associated with survival after a diagnosis of ovarian cancer.

Metformin use and survival in people with ovarian cancer: A population-based cohort study from British Columbia, Canada

There is an active debate regarding whether metformin use improves survival in people with ovarian cancer. We examined this issue using methods designed to avoid immortal time bias-as bias that occurs when participants in a study cannot experience the outcome for a certain portion of the study time. We used time-dependent analyses to study the association between metformin use for all 4,951 patients diagnosed with ovarian cancer in 1997 through 2018 in the province of British Columbia, Canada. Cox proportional hazards models were run to estimate the association between metformin and survival in the full cohort of ovarian cancer patients and among a cohort restricted to patients with diabetes. Metformin use was associated with a 17 % better ovarian cancer survival in the full cohort (adjusted hazard ratio (aHR) = 0.83 (95 %CI 0.67, 1.02)), and a 16 % better ovarian cancer survival for serous cancers patient's cohort (aHR = 0.84 (95 %CI 0.66, 1.07)), although both were not significant. However, a statistically significant protective effect was observed when restricting to the diabetic cohort (aHR = 0.71 (95 %CI 0.54-0.91)), which was also seen among serous cancers (aHR = 0.73 (95 %CI 0.54-0.98)). Metformin use was associated with improved ovarian cancer survival. The lack of statistical significance in the full cohort may reflect that diabetes is associated with reduced cancer survival, and thus diabetes itself may offset the benefit of metformin when examining the full cohort. Future research should examine metformin use among non-diabetic ovarian cancer patients.