Inter-individual variation in ovarian reserve after gonadotoxic treatment in female childhood cancer survivors – a genome-wide association study: results from PanCareLIFE

Abstract

ObjectiveWe aimed to discover new variants associated with low ovarian reserve after gonadotoxic treatment among adult female childhood cancer survivors using a genome-wide association study approach. DesignGenome-wide association study. SubjectsA discovery cohort of adult female childhood cancer survivors, from the pan‐European PanCareLIFE cohort (n=743; median age: 25.8 years), excluding those who received bilateral ovarian irradiation, bilateral oophorectomy, central nerve system or total body irradiation, or stem cell transplantation. Replication was attempted in the USA‐based St. Jude Lifetime Cohort (n=391; median age: 31.3 years). ExposureFemale childhood cancer survivors are at risk of therapy‐related gonadal impairment. Alkylating agents are well‐established risk factors, and the inter‐individual variability in gonadotoxicity may be explained by genetic polymorphisms. Data were collected in real-life conditions and cyclophosphamide equivalent dose was used to quantify alkylation agent exposure. InterventionNo intervention was performed. Main Outcome MeasureAnti‐Müllerian hormone (AMH) levels served as a proxy for ovarian function and findings were combined in a meta‐analysis. ResultsThree genome-wide significant (<5.0x10-8) and 16 genome-wide suggestive (<5.0x10-6) loci were associated with log-transformed AMH levels, adjusted for cyclophosphamide equivalent dose of alkylating agents, age at diagnosis, and age at study in the PanCareLIFE cohort. Based on effect allele frequency (EAF) (>0.01 if not genome-wide significant), p-value (<5.0×10−6), and biological relevance, 15 SNPs were selected for replication. None of the SNPs were statistically significantly associated with AMH levels. A meta-analysis indicated that rs78861946 was associated at borderline genome-wide statistical significance (Reference/effect allele: C/T; EAF: 0.04, Beta (SE): −0.484 (0.091), p‐value= 9.39×10−8). ConclusionThis study found no genetic variants associated with a lower ovarian reserve after gonadotoxic treatment, as the findings of this GWAS were not statistically significant replicated in the replication cohort. Suggestive evidence for potential importance of one variant is briefly discussed, but the lack of statistical significance calls for larger cohort sizes. As the population of childhood cancer survivors is increasing, large-scale and systematic research is needed to identify genetic variants that could aid predictive risk models of gonadotoxicity and as well as fertility preservation options for childhood cancer survivors.