Experimental studies on the leukemogenesis in mice. Part 2. Effects of thymectomy and splenectomy on the incidence of leukemia by X-ray-irradiation in RF mice

With the object to elucidate the role played by thymus and spleen in radiation leukemogenesis, effects of thymectomy and splenectomy on the induction of leukemia in RF mice by X-ray-irradiation were studied, dividing lymphocytic leukemia into thymic type and non-thymic type. As the result it has been clarified that thymectomy mainly inhibits the occurrence of the thymic type lymphocytic leukemia while splenectomy on the occurrence of the non-thymic type lymphocytic leukemia. As for the mechanism of this inhibition, a discussion was made on the significance of thymus and spleen as the organs that are constituted of the cells most susceptible to neoplastic transformation. After both thymectomy and splenectomy not a single mouse developed leukemia when exposed to X-ray-irradiation.