We investigated, cisplatin - induced intrinsic pathway of apoptosis in APL cells by western blot analysis of the expression levels of proapoptotic proteins (e.g. Bax, cytochrome, and caspase 3) and anti-apoptotic protein (Bcl-2) by western blotting both in control and treated cells. The gene discussed is BAX; the disease is acute promyelocytic leukemia.