In this study, we evaluated the synergistic effect of ITs (Mel-14-PE38KDEL or 9.2.27-PE38KDEL) targeting CSPG4 and one of the five small molecule Bcl-2 family inhibitors, ABT-737 and ABT-263 (specific for Bcl-2, Bcl-xL, and Bcl-w), ABT-199 (specific for Bcl-2), A-1155463 (specific for Bcl-xL) [28], or S63845 (specific for Mcl-1) [29, 30] in GBM xenograft cells, and melanoma and breast cancer cell lines. The gene discussed is MCL1; the disease is breast cancer.