Combination of Smac mimetics with inhibitors of platelet-derived growth factor receptor (PDGFR), insulin-like growth factor 1 receptor (IGF1R) and epidermal growth factor receptor (EGFR) significantly increases apoptotic cell death compared to monotherapy in human glioblastoma cells [162], and combined therapy of Smac mimetics with inhibitors of FMS-like tyrosine kinase 3 (FLT3) and BCR-ABL resulted in similar effects against leukemia [163,164]. Here, IGF1R is linked to leukemia.