[Antitumor activity of chlorella extract, PCM-4, by oral administration].

The antitumor activity of a water-soluble substance extracted from Chlorella regulararis S-50, PCM-4, against murine transplanted tumors was investigated. PCM-4 is composed of sugar (25.7%), protein (51.5%) and nucleic acid (18.7%). By oral administration of PCM-4, both the growth of Sarcoma 180 and Meth A, subcutaneously implanted into mice, and ascites hepatoma AH 44 and AH 41C, intravenously implanted into rat, was inhibited. PCM-4 also showed antitumor activity against Sarcoma 180 and Meth A by intraperitoneal administration. The finding that PCM-4 has no direct growth-inhibition effect on tumor cells in vitro suggests that the antitumor activity of PCM-4 be elicited from the host-mediated response system.