To investigate whether antagonizing BCL-2 family proteins can kill osteosarcoma cells, we tested the sensitivity of six established osteosarcoma cell lines to inhibition of BCL-2 (ABT-199), MCL-1 (S63845) and/or BCL-xL (A-1331852) (Supplementary Fig. 1) for 24 h using CellTiter-Glo 2.0 cell viability assays. The gene discussed is MCL1; the disease is osteosarcoma.