Distant metastasis from subcutaneously grown E0771 medullary breast adenocarcinoma.

Breast cancer treatments are most effective when initiated early, with very poor efficacy against metastatic disease. In seeking a readily metastasizing mouse breast cancer model to facilitate the search for effective therapies, E0771 medullary adenocarcinomas implanted subcutaneously in syngeneic C57BL/6 mice were studied.Standard pathological, histological and immunological methodologies were used.The aggressive estrogen receptor-positive tumor invaded locally into the peritoneal cavity in 56% of mice, as well as metastasizing to the lungs in 52% of mice. The metastasis was a spontaneous event and immunosuppression was seen (e.g. generation of lyphokine activated killer cells and allogeneic cytotoxic T lymphocytes cytolytic activities ex vivo were suppressed). Other pathological events noted as the tumor progressed were: bloody ascites (56%) and shock (72%), both attributed to local (peritoneal) tumor invasion.The E0771 metastatic breast cancer model, which mimics the human disease, should be useful in testing new treatments against this disease and/or in examining the metastatic process.