Metaplastic breast carcinoma appears to have little HER-2/neu overexpression, with a positive rate of 7–14%, unlike other high-grade breast carcinomas, which have a HER-2 positivity rate of 25–30% (5,12,17,18), suggesting that metaplastic carcinoma may have an alternative biology to high-grade invasive ductal carcinoma (18). This evidence concerns the gene ERBB2 and metaplastic breast carcinoma.