Objective To provide experimental materials for exploring the function of breast cancer susceptibility gene 2(BRCA2) gene by establishing of an mouse immortalized mammary gland epithelial cell line as a cell model system.Methods In this study,the primary mouse mammary epithelial cells were isolated and purified by enzyme digestion and differential centrifugation.The resulting primary mouse mammary gland epithelial cells were transducted with lentivirus expressing human telomerase (hTERT) gene,and screened by hygromycin B.The surviving epithelial cells were further characterized by morphology observations and cytokeratin marker detection.Results Immortalized mouse mammary epithelial cells were obtained by infection of MMECs with lentivirus expressing human telomerase(hTERT) gene,screened by hygromycin B.Morphology observations and detection of the cytokeratin marker showed the immortalized MMECs had a typical morphology of luminal epithelial cells with strong expression of cytokeratin 14.Conclusion An immortalized mouse luminal epithelial cell line is successfully established with an uniform morphology,which provides a cell model system for the future exploration on BRCA2-related tumorigenesis.