The authors have described G2/M arrest, activation of caspase-9 and caspase-3/7 (but not caspase-8) in the metastatic breast cancer cell line MDA-MB-231 by boldine, which also down-regulates Bcl-2 and heat shock protein 70 and up-regulates Bax. This evidence concerns the gene CASP9 and breast carcinoma.