Consistent with our observation of an increased frequency of nucleocytoplasmic ß-catenin in human DCIS relative to benign breast epithelium (Figure 2B; Table 3), we detected nucleocytoplasmic ß-catenin in murine mammary DCIS tumors induced by overexpression of a mutationally activated HER2/neu transgene (NDL; Figure 3). The gene discussed is ERBB2; the disease is ductal breast carcinoma in situ.