Quantitative and histochemical analysis of Cu, Zn, and Fe in spontaneous and induced primary tumors of rats.

The heavy metals, Zn, Cu, and Fe, have been investigated quantitatively and histochemically in certain animal tumors, viz., DAB-induced liver tumor, fibroma, benzpyrenefibrosarcoma, adenoma and carcinoma of mammary gland, and carcinoma of prostate. The findings in these tumors have been compared with normal liver, spleen, tendon, mammary gland, and prostate tissue. I t was demonstrated that Cu increases while Zn seems to decrease in the tumors investigated, but no characteristic behavior for Fe could be found in neoplastic tissue. In addition, it appears that, in neoplastic cells, these heavy metals are concentrated preferentially in the nuclei when compared either with neoplastic cytoplasm or with normal cells. Histochemical investigations were carried out by the "sulfide-silver-technic" of Timm (13), and the staining of spodograms by use of magnesium dithizonate (14). These technics support the results of quantitative determinations.