Chegaev et al. found that doxorubicin has a more potent cytotoxicity on both doxorubicin-sensitive and doxorubicin-resistant osteosarcoma cells in the presence of H2S than that in the absence of H2S. The inhibitory effect of H2S on the P-glycoprotein in the doxorubicin-resistant osteosarcoma cells, resulting in the reduced efflux of doxorubicin and increased intracellular accumulation of DOXO, might be involved in the enhanced effectiveness of doxorubicin (Chegaev et al., 2016). The gene discussed is ABCB1; the disease is osteosarcoma.