We could not identify such a correlation, since the majority of our cases comprised benign and negative HER-2 samples, concordant with the findings of Madan et al.12Claudin-4 was found to correlate with HER-2 immunohistochemical expression in 299 cases of invasive ductal carcinoma,20 but another report did not find this correlation in 412 tumors.31 This evidence concerns the gene ERBB2 and invasive ductal breast carcinoma.