On thrombocytopenia developing in mice bearing a spontaneously metastasizing tumor.

Thrombocytopenia was observed in mice during development and metastatization of Lewis Lung Carcinoma (3LL). Survival of labelled platelets was not modified throughout the observation period, whereas platelet turn-over was markedly reduced, suggesting a defective platelet production. An increase in the splenic platelet pool could be excluded. Other hematological data indicated that, among blood cells, only platelet production was impaired. The origin of thrombocytopenia occurring during spontaneous metastatization of 3LL seems to be quite different from the mechanism of the decrease in platelet count observed after rapid intravenous injection of the same tumoral cells.