HER2 Expression Status and Prognostic, Diagnostic, and Demographic Properties of Patients with Gastric Cancer: a Single Center Cohort Study from Iran.

Background: The fourth most prevalent cancer worldwide and a major cause of death in developing countries is gastric cancer (GC). Human epidermal growth factor receptor 2 (HER2), is a proto-oncogene expressed in different solid tumors. This study aimed to evaluate possible associations of HER2 expression status with survival rate, age, sex, tumor grade, histopathological type, and primary tumor location in patients with GC. Methods: Subjects were enrolled in this cohort study after consideration of inclusion and exclusion criteria. Biopsy specimens were stained using immunohistochemistry. Samples with a score of 3+ were considered to exhibit HER2 overexpression. The mentioned variables were extracted from patients’ files as well as by clinical evaluation. The Kaplan-Meier method was applied for analyzing the survival rate and Chi square for possible factor associations. Results: A total of 210 patients (25.2% female and 74.8% male) were enrolled. In a 5-year follow-up (adherence rate: 45.7%), the average survival was 9.4±10.9 months. HER2 overexpression was evident in 24%. There was no statistically significant association found between HER2 expression and primary tumor location (p-value=0.63), histopathological type (p-value=0.72), or tumor grade (p-value=0.051). Furthermore, no statistically significant links were apparent with tumor grade in either male or female groups as well as patients aged ≥60 and ˂60 years (all p-values >0.05). Moreover, no statistically significant association was detected between HER2 expression status (p-value=0.88), sex (p-value=0.31), and age (p-value=0.055) with patient survival. Conclusions: No statistically meaningful association was found between all parameters examined and HER2 expression status. Divergence of the results from earlier studies might be due to genetic variation. Thus, performing a meta-analysis on certain races might be helpful for clarification.