MCL1 and breast cancer: Our results show consistently high Mcl-1, but variable Bcl-2 and Bcl-xL protein levels in a cell line panel of different BC subtypes, including Luminal A-like (MCF-7), Luminal B-like/Her2-positive (BT-474), Her2-positive (HCC-1954, SKBR3), and TNBC cells (MDA MB-231) [37, 38] under hypoxic conditions (Fig. 1b).