Letter to the Editor regarding the paper by Park et al., Extra-gain of HER2-positive cases through HER2 reassessment in primary and metastatic sites in advanced gastric cancer with initially HER2-negative primary tumours: Results of GASTric cancer HER2 reassessment study 1 (GASTHER1). (April 2017) - Ieni, A.; Angelico, G.; Zeppa, P.; Tuccari, G.