G3139 is used in anticancer treatments with other chemo/radio-therapeutic drugs in tumor types that include melanoma, chronic lymphocytic leukemia, B-cell lymphoma, breast cancer, and many other solid tumors, by stimulating the opening of alternative outer mitochondrial membrane channels which cytochrome c can pass through inducing apoptosis [59,60,61,62,63,64]. The gene discussed is CYCS; the disease is B-cell chronic lymphocytic leukemia.