mBR6004

This model was developed from a breast tumor in a MMTV-PyVT transgenic (MMTV-PyMT) mouse. The MMTV-PyVT transgene (MMTV-PyMT) has the mouse mammary tumor virus (MMTV) long terminal repeat upstream of a cDNA sequence encoding the Polyoma Virus middle T antigen (PyVT). Transgenic mice are viable, but show loss of lactational ability coincident with transgene expression. Female carriers develop palpable mammary tumors as early as 5 weeks of age. Adenocarcinomas arise in virgin and breeder females as well as males, which are multifocal, highly fibrotic, and involve the entire mammary fat pad. Males also develop adenocarcinoma of the seminal vesicles and hemangiomas. Pulmonary metastases are observed in 80-94% of tumor-bearing female mice. Transgene expression is detected at high levels in male and female mammary glands. Lower levels are detected in salivary gland, seminal vesicles, ovaries, and lungs (believed to be the result of pulmonary metastases).