In survivors of ALL or osteosarcoma, carrying the ABCC2-rs3740066-GG genotype or the SLC22A6-rs6591722-AA genotype increased the risk of cardiomyopathy 5–10 years after cancer diagnosis compared to other genotypes (p = 7.11 × 10−4, p = 1.71 × 10−3, respectively). The gene discussed is ABCC2; the disease is osteosarcoma.