Effects of gallium chloride oral administration on transplanted C3HBA mammary adenocarcinoma: Ga, Mg, Ca and Fe concentration and anatomopathological characteristics.

To determine the influence of the length of the treatment on the anatomopathological and biochemical intratumor changes induced by gallium, we treated C3H BA mammary adenocarcinoma-bearing C3H/HeJ mice with gallium chloride daily, for a period of either 21 or 42 days. In both cases the same dose of 200 mg/kg/24h was administered. An increase of collagen fibrosis in treated tumors as opposed to controls was only noted after 42 days, as well as a significant decrease of the intratumor magnesium and calcium concentrations that could be responsible for a reduction in the metabolic activities of the malignant cells. Remarkable intratumor gallium concentrations (38.4 +/- 30.3 nmol/g after 21 days of treatment; 13.4 +/- 7.3 nmol/g after 42 days where the necrosis is much more important) are obtained after this oral administration. There is no renal toxicity and a higher tumor/kidney concentration ratio is obtained than after acute parenteral administration. The effect of gallium may be different according to the mode of administration: it may be more cytotoxic after parenteral administration, while after oral administration it may act as a better metabolic regulator with a more selective tumor uptake and fewer side effects.