Allotransplantation of K248 feline mammary carcinoma cell line in cats. A model for monoclonal antibody guided detection and therapy of human breast cancer.

In response to the need for appropriate models for monoclonal antibody guided detection and therapy of human breast cancer, we developed an allogeneic host-tumor model by injecting K248C and K248P cells into cats. A comparison between the K248C- and K248P-induced tumors with respect to biological behavior and histological appearance was made throughout the study. Allotransplantation of tumor cells was performed both in newborn cats and fetal cats between days 42 and 51 of gestation, but only tumor cells injected by the latter approach resulted in tumor growth in all animals injected. Both tumor cell lines gave rise to progressively growing tumors at the site of injection, metastatic spread of tumor cells to various organs, and death from progression 2-4 months after birth. The predominant histological appearance of the K248C and K248P allografts resembled the cribriform and tubulo-papillary growth patterns, respectively, of the original tumor from which the two cell lines were derived. Autopsy of 1-day kittens showed that metastasis started already in the fetus in the short period between injection of tumor cells and birth. Three predominant patterns of metastases were identified: the pulmonary/pleural type, the abdominal type, and the soft tissue type. A lower incidence of metastases was found in bones and brain. The K248C allografts formed significantly more metastases of the abdominal type than K248P tumors (p less than 0.05). No difference in survival was observed between animals with K248C or K248P allografts. The difference in take rate and latency period between K248C and K248P in athymic mice does not seem to be present in the feline host. The similarity of the present model to spontaneous feline and human mammary carcinoma is discussed.