Since the present study strongly suggested the involvement of dynamin 2 protein in PpIX efflux, we have preliminarily examined the cellular exocytosis of PpIX in human prostate cancer PC-3 and DU-145 cells by using two-photon excitation imaging and observed the exocytosis of PpIX initiated by Ca2+ release from the caged-Ca2+ compound o-nitrophenyl-EGTA (NP-EGTA, Molecular Probes) upon stimulation with a flash of UV light for 1/16 sec (data not shown)65. This evidence concerns the gene DNM2 and prostate carcinoma.