BCL2 and cancer: These data, together with the findings of the early translocation of Bax from the cytosol to mitochondria following PDT in Bax-replete MCF-7c3 cells, as well as the suppression of apoptosis in these cells upon treatment with Bax-AS, clearly establish that Bax is the sole proapoptotic Bcl-2 family member essential for apoptosis in these human cancer cells in response to the two test inducers.