During the study period, 858 invasive breast carcinomas were tested for HER2 overexpression and 11.4% (98/858) were found to be HER2 positive: 9.6% (48/501) unifocal, 15.2% (48/315) multifocal, and 4.8% (2/42) diffuse tumors. Here, ERBB2 is linked to invasive breast carcinoma.