Allensworth et al. showed that in breast cancer cell lines, SMAC mimetic birinapant induced cell death as a single agent in TRAIL-insensitive SUM190 (ErbB2-overexpressing) cells and significantly increased potency of TRAIL-induced apoptosis in TRAIL-sensitive SUM149 (triple-negative, EGFR-activated) cells37. The gene discussed is ERBB2; the disease is breast cancer.