Copper and zinc levels in normal and malignant tissues.

The copper and zinc levels in 53 malignant and 47 normal human tissue samples were measured. In the malignant tissues, the mean copper concentration was 46% higher (P less than 0.001) than in the normal ones. Analysis of the individual organs showed this increment to be statistically significant in malignancies of the large bowel, stomach, urinary bladder and female reproductive organs, while in cancer of the breast, kidney and testis, the increase in copper level was not significant. The mean zinc concentration in the malignant tissues was not significantly different from that in the corresponding normal tissue specimens (-11%; P less than 0.2). In breast cancer, however, tissue zinc levels were increased by 72% (P less than 0.01), and decreased markedly in carcinoma of the kidney (-73%). A hypothesis for the possible mechanism involving elevated tissue copper levels in biological damage (previously caused by free radicals) which may be responsible for the malignant process, is presented and discussed.