MCL induces the cell death of breast cancer cells by increasing mitochondrial fission, decreasing mitochondrial membrane potential, releasing reactive oxygen species (ROS) generation, disrupting PARP and up-regulating Drp1 expression [29]; MCL enhances the cisplatin sensitivity in MCF-7cells of breast cancer in vitro and in vivo via increasing the expression of ALDH+ (the marker of breast cancer stem cell) and up-regulating Krüppel-like factor 4 (KLF4, cell self-renewal and maintenance of pluripotency) expression [30]. This evidence concerns the gene KLF4 and breast cancer.