Frequent Development of Murine T‐Cell Lymphomas with TcRα/β(+), CD4(‐)/8 Phenotype after Implantation of Human Inflammatory Breast Cancer Cells in BALB/c Nude Mice

Tumors developed quite frequently in some of the visceral organs, including spleen and liver, in BALB/c nude mice upon subcutaneously xenografting surgical specimens from five different inflammatory breast cancer patients. All of these tumors developed within two and a half months to one year after the subcutaneous inoculation of surgical specimens. From these tumors, five independent transplantable tumors, including tMK‐2, tHK‐1, tYK‐1, tYK‐2 and tTY‐1 have been established. Chromosome analysis, morphologic studies by light and electron microscopy and phenotype analysis indicated that these tumors are of mouse origin. The tMK‐2 tumor was highly metastatic to the spleen and liver when it was subcutaneously transplanted into the right scapular region. In addition, the region where the tMK‐2 tumor cells were subcutaneously inoculated showed an apparently inflammatory process represented by erythema. After subcutaneous inoculation into the right scapular region, tHK‐1, tYK‐1,2, and tTY‐1 tumors also metastasized to some of the visceral organs, including spleen and liver. From these tumors, in vitro cell lines were established. The cells grew in a stromal‐cell dependent manner under in vitro culture conditions. The cells were again tumorigenic at the inoculated region and metastasized to various organs, including liver and spleen, of BALB/c nude mice. Histological examination revealed that the tumors showed features of malignant lymphoma. Phenotypically, these five tumors expressed early T lymphocyte markers as revealed by anti‐mouse anti‐TcR4aL/β, anti‐CD3, CD4 and CDS monoclonal antibodies. To our knowledge, these cell lines are the first T‐cell lines showing the phenotype of extrathymically differentiated T‐cells in the liver.