Multidrug resistance protein 1 (MDR1) that is encoded by gene ATP-binding cassette, subfamily B (MDR/TAP), member 1 (ABCB1) has been shown to serve as a plausible factor in doxorubicin resistance, which was validated to be linked with poor outcomes in many osteosarcoma studies [16, 17], but whether there would be more valuable biomarkers remained to be explored. The gene discussed is ABCB1; the disease is osteosarcoma.