BCL2 and breast cancer: Inhibition of expression of Bcl-2 family members by antisense oligonucleotide or dominant negative inhibitor Bcl-xs has already been shown to promote apoptosis and to sensitize cells to chemotherapy-induced apoptosis.54 Despite the antiapoptotic and chemoresistant effects favoring tumor survival, Bcl-2 prolongs cell cycle and decreases tumor cell proliferation, and these functions may account for the association of Bcl-2 in favorable breast cancer outcomes.