Canine transmissible venereal sarcoma: transplantation studies in neonatal and adult dogs

taneous canine transmissible venereal sar-comas (CTVS) showed that the subcutaneous inoculation of 1 XI08 viable tumor cells con-sistently produced positive tumor takes in 16 days in 880/0 (15/17) of non-preconditioned adult mongrel dogs. After a period of rapid growth, the tumor regressed spontaneously in 2-6 months. Sixteen newborn puppies from normal mothers developed malignant neo-plasms within 15 days after inoculation. These grew quickly, enlarged, ulcerated, and metas-tasized to other organs. In contrast, 36 of 43 puppies (84%), whose dams either failed to develop tumors or had borne tumors in our laboratory, developed tumors. Some of the 36 puppies with neoplasms had latent periods of up to 67 days, and the tumors invariably grew much more slowly than in puppies from un-exposed dams. Spontaneous regression was seen in about 20 % of the animals. The growth pattern of the tumor, benign or malignant, seemed to reflect the immunologic compe-tence of the host, i.e., benign in normal adults and malignant in puppies. There appeared to be an inverse relationship between the maxi-mum size the tumor attained and the propor-tion of small lymphocyte-like cells present in the viable tumor cell suspension. In contrast to previous reports, present findings on malig-nant behavior of experimental CTVS in normal puppies indicate the possible usefulness of this neoplasm for studies of experimenta