Confirmation of genetic risk markers of platinum-induced ototoxicity

Background: Platinum compounds such as cisplatin or carboplatin are potent antineoplastic agents widely used for a variety of cancer types. Unfortunately, their use leads to dose-limiting side effects such as ototoxicity. Our study aimed at investigating the predictive value of 11 candidate genetic markers in a large non-selected pediatric population of cancer survivors who had been treated with cisplatin and/or carboplatin.Materials and Methods: As a part of the PanCareLIFE study, the ototoxicity study included 2,696 survivors from 7 European countries treated with cisplatin and/or carboplatin for childhood cancer, resulting in the largest clinical European cohort assembled for this late-effect study. Hearing loss was audiologically classified using the Münster Classification. Three groups were defined, i.e., no hearing loss, minor hearing loss, and clinically relevant hearing loss. Patients were genotyped for single nucleotide polymorphisms (SNPs) in 7 candidate genes. Genetic association analyses were performed considering non-genetic covariates.Results: 900 patients were included in the final genetic analysis. Multinomial logistic regression was performed to model the relationship between the predictors and membership in the hearing loss group. The model explained 25% of the variance in hearing loss and correctly classified 58% of cases. Significant unique contributions were made by SLC22A2 rs316019 (P=0.017), age at the start of platinum treatment (P=1.46x10-17), cranial radiation (P=5.42x10-6), and the cumulative dose of cisplatin (P=5.86x10-19). Addition of the rs316019 genetic marker to the non-genetic risk factors (age, dose, cranial radiation) improved the area under the ROC curve only marginally (0.731 vs. 0.730).Discussion: Our study confirmed one potential genetic marker, rs316019 in SLC22A2. Its predictive value, however, is low.Conclusion: Due to the heterogeneity of results from genetic association studies performed so far, the evidence seems not yet sufficient to recommend screening for specific markers. Advances in the understanding of the pathophysiologic mechanisms of cisplatin-induced ototoxicity, as well as future genome-wide association studies, may help identify suitable genetic markers.Acknowledgement: This work was supported by the PanCareLIFE project that has received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 602030