The major findings of this study are that (i) IP3R2 is a determinant of the sensitivity of Bcl-2-dependent ‘primed to death' DL-BCL cells toward the apoptotic effect of TAT-IDPS, and (ii) Bcl-2-dependent cancer cells may be addicted to high levels of Bcl-2 to suppress aberrant pro-apoptotic Ca2+ signals. This evidence concerns the gene BCL2 and cancer.