Validation of transgenic models of breast cancer: ductal carcinoma in situ (DCIS) and Brca1-mutation-related breast cancer.

Available mouse models of ductal carcinoma in situ (DCIS) and BRCA1-mutation-related breast cancer are reviewed. The best validated mouse models of human DCIS are the conditional estrogen receptor α in mammary tissue (CERM) model initiated by deregulated estrogen receptor α and the serial explant mouse model initiated by p53 deficiency. At present the most useful and best validated mouse model of BRCA1-mutation-related breast cancer uses the cre-lox system to make a conditional Brca1 deletion targeted to mammary epithelial cells. The major shortcoming of the non-conditional Brca1 models is the high incidence of non-mammary tumor development. The use of mammary gland transplants or explants from these mice into nude hosts is one approach that could be used to circumvent this deficiency. Development and validation of a Brca1-mutation-related mouse model of basal cell breast cancer is an important next step.