ERBB2 and invasive ductal breast carcinoma: For example, the highest level was found in invasive ductal carcinoma (IDC) (n = 772) when compared to invasive lobular carcinoma (ILC) (n = 205) and normal breast tissues (n = 111), as well as in the HER2-positive subgroup (n = 157) when compared to the HER2-negative group (n = 570) or normal breast tissues (n = 111).