HER2 in Colorectal Cancer: The Long and Winding Road From Negative Predictive Factor to Positive Actionable Target.

Human epidermal growth factor receptor 2 () is a well-known oncogenic driver in different tumors and an approved therapeutic target in breast and gastroesophageal cancer. In metastatic colorectal cancer, only 3% to 5% of patients present with alterations: somatic mutations and amplifications. was first assessed as a biomarker of resistance to anti- therapy; however, in more recent years, its role as a potential actionable target has emerged. In this article, we discuss the predictive and prognostic value of in metastatic colorectal cancer, its emerging role as an actionable therapeutic target, and its possible future developments.