On the Mechanism of Urethan Leukemogenesis in Newborn C57BL Mice: II. Influence of Thymectomy and of Subsequent Thymus Reimplantation¹

Urethan leukemogenesis was found to be fairly potent in C57BL mice when the treatment was begun soon after birth (35% incidence) but very weak when the treatment was begun at about 45 days of age (6% incidence). The inhibitory effect of thymectomy on urethan leukemogenesis was not reversed by subsequent implantation of syngeneic newborn thymus, in contrast to such a reversal in the case of radiation leukemogenesis. Possible reasons for the difference are discussed.