ERBB4 and colorectal carcinoma: HER3 mutations, detected in up to 11% of CRCs, are associated with malignant transformation in vitro.[30] HER4 overexpression was documented in 17% of CRC samples and mutations were detected in 2.9% of CRCs.[28, 31] HER3 and HER4 expression, as well as phosphorylated HER3 and HER4, were associated with worse prognosis.[32]