Genetic variation may modify ovarian reserve in female childhood cancer survivors

Abstract

Are genetic polymorphisms, previously identified as being associated with age at menopause in the healthy population, associated with ovarian reserve and predicted age at menopause in adult long-term survivors of childhood cancer? The CT genotype of rs1172822 in the BRSK1 gene is associated with lower serum anti-Müllerian hormone (AMH) levels and a younger predicted age at menopause in adult survivors of childhood cancer. Gonadotoxicity is a well-known late side effect of chemotherapy and radiotherapy in adult survivors of childhood cancer. In the healthy population, several genetic polymorphisms are associated with age at natural menopause. Currently, data on the impact of previously identified variants in gene loci associated with ovarian reserve in adult long-term survivors of childhood cancer are lacking. We performed a pilot study in a single-centre cohort of adult female Caucasian childhood cancer survivors (n = 176). We determined serum AMH levels (a marker of ovarian reserve) in adult survivors of childhood cancer (n = 176) and studied single nucleotide polymorphisms (SNPs) previously reported to be associated with age at natural menopause: BRSK1 (rs1172822), ARHGEF7 (rs7333181), MCM8 (rs236114), PCSK1 (rs271924), IGF2R (rs9457827) and TNF (rs909253). Association analysis was performed using the additive genetic model. Linear regression was conducted to assess the effect of significant polymorphisms in two previously published menopause prediction models. The CT genotype of rs1172822 in the BRSK1 (BR serine/threonine kinase 1) gene was negatively associated with serum AMH levels in our cohort (odds ratio: 3.15, 95% confidence interval: 1.35-7.32, P = 0.008) and significantly associated with the predicted age at menopause (P = 0.04). The other five SNPs were not associated with serum AMH levels. This is a pilot study showing preliminary data which must be confirmed. To confirm our findings and enlarge the project, a nationwide genome-wide association (GWA) project on the ovarian reserve in female survivors of childhood cancer should be performed, including a replication cohort. Our findings support the hypothesis that previously identified genetic polymorphisms associated with age at menopause in healthy women may have an effect on the onset of menopause in female survivors of childhood cancer. Our study highlights a new aspect of the influences on the ovarian reserve after childhood cancer, which should be investigated further in a nationwide GWA study. Eventually, this information can help us to improve counselling on fertility preservation prior to cancer treatment based on genetic factors in individual patients. W.D. is supported by the Paediatric Oncology Centre Society for Research (KOCR), Rotterdam, The Netherlands. J.S.E.L. has received fees and grant support from the following companies (in alphabetic order): Ferring, Genovum, Merck-Serono, Organon, Schering Plough and Serono. All other authors have nothing to disclose.