ABCC2 and osteosarcoma: Material and Methods: Germline polymorphisms in MTHFR, SLC19A1, ABCB1, ABCC2, ABCC3, ERCC1, ERCC2 and GSTP1 genes were determined for association studies in 69 patients diagnosed with localized osteosarcoma who enrolled in the prospective GEIS-33 trial.