Tumor cells exhibit consistent abnormalities in calcium regulation. The present disclosure teaches methods by which such differences are exploited to induce Apoptosis selectively in tumor/cancer cells while sparing normal cells. These methods are based upon employing drugs that, acting in synergistic combinations, trigger selective killing of malignant cells. Since the invention is based upon fundamental cell cycle requirements, to the extent that calcium handling abnormalities are a general characteristic of the malignant state, the methods presented here are widely applicable regardless of tissue of origin and degree of cellular de-differentiation.