Summary Several cohorts of cancerous mice were continuously dosed with 2,2′‐bipyridyl dibutyltin dichloride, 1,10‐phenanthroline dibutyltin and histidine dibutyltin; presented at 1 ppm and 10 ppm in drinking water. Tumour growth rates were significantly reduced. Tributyltin fluoride (TBTF) applied dermally, using dimethyl sulfoxide (DMSO) as the carrier, over the tumour site was ineffective. Variation in thymus and spleen weight between controls and tin‐exposed mice indicates a lymphatic involvement. Analysis of mouse tissue for total tin content showed high tin concentrations in the thymus and spleen.

Summary, A comprehensive study of the scientific literature regarding tin content in normal and pathogenii; himiiin tissue has disclosed that various organotin materials retard both the onset and growth of cancer in laboratory animals, and decreased tissue tin in humans may be associated with lumour development.Initial studies by the authors have shown that the thymus gland of the mouse possesses a relatively high concentr;ition of tin and is also the major site of accumulation for I'C-labelied tri-n-biityltin fluoride (TBTF), When mammary cancer-prone mice with transplanted tumours were orally dosed continuously with this agent in their drinking water, the tumour growth rate was significantly reduced. Both mouse mammary tumours and human lung tumours show low tin contenl compared to normal body tissue.