ERBB2 and breast carcinoma: In agreement with previous studies on breast carcinomas,3 we confirmed that TOPOIIα is rarely amplified in the absence of HER-2 amplification, that it is co-amplified with HER-2 in dysplasia (LGD and HGD) and ADC, and that the HER-2 gene copy number, because of clustering, was higher than the TOPOIIα copy number.