ERBB2 and ductal breast carcinoma in situ: In DCIS tumors, 100% of HER2/neu-positive cases (3/3) exhibited nucleocytoplasmic ß-catenin, whereas only 50% of HER2/neu-negative samples (7/14) were nucleocytoplasmic ß-catenin-positive, but statistical power was limited by small sample size.