PSEN1 and nasopharyngeal carcinoma: 48-h transfection with siRNA directed against PSEN1 significantly increased the ionomycin- (Fig. 5, D and E) and TG-mediated (Fig. 5, F and G) elevations in Ca2+ from NPC fibroblasts compared with NPC fibroblasts transfected with a negative nontargeting control.