TUMOR-LOCALIZING ACTIVITY OF PORPHYRIN AND ITS AFFINITY TO LDL, TRANSFERRIN

We spectrochemically analyzed 12 Ga-Metal porphyrins (Ga-Cn-P) with di fferent degrees of hydrophobicity, and observed a close association be tween the in vivo Ga-Cn-P localization in the tumor and its affinity t o transferrin and LDL. Image analysis of tumors with 99m-Tc-STA-R12, a porphyrin-scintigraphic agent, revealed STA-R12 localization in the t umor tissue alone about 1 h after intravenous infusion. Our results su ggest the importance of endocytosis mediated by transferrin as well as LDL that have been reported as a mechanism of the tumor-localizing ac tivity of porphyrin.