SMPD1 and melanoma: However, genetic ASMase overexpression in the angiogenic compartment of radiation-incurable B16-F1 melanomas resulted in significant increase in the radiation-induced apoptotic response (19±2% vs. 7±1% at 34 Gy, and 27±2% vs. 10±2% at 41 Gy; P<0.005 each; Fig. 6D).