The investigation reported was undertaken to determine the factors concerned in the low metastatic rate of a transplantable lymphoblastic lymphoma in the hamster. Tumor cells were found to be present in the blood stream on the 7th day after transplantation, but the great majority of animals lived for another month without the development of metastases. However, removal of the primary tumor on the 13th day of growth was followed by metastasis in all the animals so treated. Investigation indicated that the inhibitory influence exerted by the primary tumor was not directed against growth of the tumor cells but rather against their stromatization.
Research supported by grants from the U.S. Public Health Service, American Cancer Society, and the Jane Coffin Childs Fund for Medical Research.