ERBB2 and gastric cancer: Several studies have analyzed changes in Her2 status after progression of first-line Her2-directed therapy to clarify the lack of survival advantage in the second-line setting of anti-Her2 therapy in Her2-positive advanced GC patients: a multicenter observational study re-evaluated the Her2 status in patients with advanced or recurrent GC refractory to trastuzumab in order to identify possible biomarkers for loss of response to Her2-targeted first-line therapy with trastuzumab [42].