MIF and breast cancer: Further, mitochondrial membrane permeability (Figure 2c) and the cleavage of PARP and lamin A were minimally affected (Figure 2d) by hormonal therapy conducted in the presence of vitamin E. Thus, the proapoptotic actions of both 4-OHT and MIF require ROS, and the IGF-1-mediated antiapoptotic action involves a mechanism that, in large part, reduces ROS in hormonally treated breast cancer cells.