Rats numbering 830 provided with a diet low in many trace elements and raised in an environment relatively free from contamination were given small amounts (5 ppm) of arsenite, germanate, stannous, chromic, cadmium, or lead ions in drinking water for their lifetimes. Mice numbering 540 taking the same diet were given 5 ppm of zirconium, antimony or niobium, or 10 ppm fluorine (as fluoride), for life. Sections of five tissues and gross tumors were made. Compared to controls, significant differences in the incidences of spontaneous tumors and malignant tumors did not appear. Tumors other than in lung, liver, adrenal, and mammary gland were significantly fewer in the germanium-fed rats. None of the trace metals was carcinogenic or tumorigenic in the doses given.

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Supported by USPHS Grant HE 05076, U. S. Army Grant Contract 2595, the American Cancer Society, and the CIBA Pharmaceutical Company.

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©1969 American Association for Cancer Research.
1969
Cancer Research, Inc.