ERBB2 and colorectal carcinoma: Diverse rates of HER2 overexpression have been reported in CRC, with rates of membrane HER2 expression ranging from 2 to 11% due to a number of factors, including analysis of distinct subgroups of patients with heterogeneous clinicopathological features, use of different antibodies for IHC and diverse scoring systems (see review by Siena et al. [12]).