However, resistance against the death-inducing effects of ABT-737 was reported in pre-clinical models, mainly due to upregulated Mcl1 protein expression in certain cancer cell types, and the abrogation of which sensitized cells to death, as seen in normal mouse embryonic fibroblast [99, 104], prostate cancer [34] and breast cancer cells [35]. Here, MCL1 is linked to breast carcinoma.