Zinc suppression of initiation of sarcoma 180 growth.

Subcutaneous administration of 80 mug zinc daily to mice that had received an intraperitoneal inoculation of 1 times 10-6 sarcoma 180 cells within the preceding 2 days resulted in protection of up to 60% of the hosts. In animals in which tumors grew, daily injections of zinc did not alter the rate of tumor cell growth. We hypothesized that the metal suppressed initiation of tumor cell reproduction, possibly by stimulation of host defense cell mechanisms.