Clinicopathologic Features and Prognosis of HER2-Positive Gastric Cancer

Background: The role of human epidermal growth factor receptor 2 (HER2) overexpression has been well established in breast cancer, with corresponding targeted therapies. In contrast, the clinicopathologic features and prognosis of HER2 overexpression in gastric cancer remain inconclusive. Methods: In this study, 334 patients with gastric cancer who received surgical resection between May 2017 and June 2021 were enrolled at a single medical center in Taiwan. HER2 status was determined by immunohistochemistry (IHC) staining or fluorescence in situ hybridization (FISH). The clinicopathologic features and survival curves of the HER2-positive and HER2-negative gastric cancer patients were analyzed. Results: The HER2-positive ratio was 7.2%. HER2-positive gastric cancer was associated with more differentiated tumors (P ¼ 0.016), more Lauren intestinal type (P ¼ 0.010), and a higher portion of Ming expanding type (P ¼ 0.033) in the univariate analysis, but only Lauren intestinal type was an independent factor in the logistic regression model (P ¼ 0.015). The overall survival and disease-free survival between the HER2-positive and HER2-negative groups were not significantly different. Patients with HER2-positive gastric cancer were more likely to have distant lymphatic recurrence than those with HER2-negative gastric cancer (P ¼ 0.026). Conclusions: HER2-positive gastric cancer is associated with intestinal histologic type and distant lymphatic recurrence, but HER2 is not an independent prognostic factor.