MNGI-12. PLEIOTROPIC MLLT10 VARIATION CONFERS RISK OF MENINGIOMA, BREAST, AND OVARIAN CANCERS

Abstract BACKGROUND Women ages 35–44 have three-fold higher risk of meningioma compared to men. Epidemiologic studies have implicated exogenous hormone use, but endogenous hormonal factors are inconsistently associated. Elevated body mass index (BMI) is consistently associated with meningioma risk in both men and women, and personal history of breast cancer has also been associated with meningioma risk. Recent genome-wide association studies (GWAS) have identified a meningioma risk locus on chromosome 10p12 near previous GWAS hits for breast and ovarian cancers. METHODS To elucidate the pleiotropic role of 10p12 variation in predisposition to diverse tumors - possibly via a common mediating factor - we performed imputation‐based fine‐mapping in three case-control datasets of meningioma (927 cases, 790 controls), female breast cancer (28108 cases, 22209 controls), and ovarian cancer (25509 cases, 40941 controls). Analyses were stratified by sex (meningioma), estrogen receptor status (breast), and histotype (ovarian), then combined using ASSET meta-analysis. Lead variants were queried for association with >700 additional traits to identify potential effect-mediators. RESULTS Two-sided ASSET meta-analysis identified a lead variant near the MLLT10 promoter (P=1.4x10-13) associated with significantly increased risk of meningioma in women (OR=1.42, 95% CI: 1.20–1.69) and non-significantly increased risk in men (OR=1.19, 95% CI: 0.91–1.57). The meningioma risk allele was also associated with ovarian cancer risk (OR=1.09, 95% CI: 1.06–1.12) and ER+ breast cancer risk (OR=1.05, 95% CI: 1.02–1.08), but protected against ER- breast cancer (OR=0.91, 95% CI: 0.86–0.96). The risk allele was associated with higher body fat percentage, waist circumference and BMI at genome-wide levels (P< 5.0x10-8), but mediation analysis adjusting for BMI did not attenuate its association with meningioma risk. CONCLUSION We identify a MLLT10 eQTL that confers risk of female meningioma, ER+ breast cancer, ovarian cancer, and obesity, but which protects against ER- breast cancer. Our results implicate a possible estrogenic mechanism underlying meningioma tumorigenesis.