Translocation of cytosolic Bcl-2-associated X protein (Bax), a pro-apoptotic factor, to the mitochondria and imbalance of the Bax/B-cell lymphoma 2 (Bcl-2), an anti-apoptotic factor, ratio induced by CIS result in caspase-3 activation. The gene discussed is CASP3; the disease is in situ carcinoma.