Of those, BCL2, which is down-regulated in radioresistant breast cancer cells and tissue (Table 1, Supplementary Figure 2), can suppress apoptosis by inhibiting the activity of caspases indispensable for apoptosis, such as caspase-3 (CASP3) (Porter and Janicke, 1999; Swanton et al., 1999). This evidence concerns the gene CASP3 and breast cancer.