Our results support these findings showing that cisplatin induces apoptosis in APL cells through changing mitochondrial membrane potential by up - regulation of pro-apoptotic protein, Bax and down-regulation of anti-apoptotic protein, Bcl-2 leading to formation of transition pores that helped to release cytochrome C into the cytoplasm. The gene discussed is CYCS; the disease is acute promyelocytic leukemia.