Single-nucleotide polymorphisms (SNPs) in genes involving drug metabolism ( ABCC2 , rs717620; MTHFR , rs1801133; ABCG2 rs2231137) and cell signaling pathways ( miR-1206 , rs2114358) have been associated with the incidence of chemo-induced OM in pediatric blood cancer patients.14 – 17 However, there are no reports on the relation between SNPs in genes involving antioxidant enzymes and chemo-induced OM in any population. The gene discussed is ABCG2; the disease is ocular melanoma.