Helicobacter pylori (HP) is a significant causative agent of gastric cancer (GC). However, the underlying mechanisms involved in its pathogenesis and association with oncoproteins are unclear. The aim of the present study was to evaluate the relationship between HP infection and human epidermal growth factor receptor 2 (HER2) expression in gastric cancer patients.
Surgery (173) or endoscopic biopsy (35) specimen of 208 patients diagnosed with GC was evaluated for the presence of HER2 and HP. HER2 expression was assessed by fluorescence in situ hybridization (FISH) method, whereas HP status was evaluated histologically. Giemsa stain was used to identify HP status, in case HP could not be recognised in routine hematoxylin eosin stained sections despite careful examination.
The median age was 63 years (27-91) and most patients were male (male/female: 149/59). Histopathologic diagnosis was adenocarcinoma in 117 (56.2%), signet ring cell adenocarcinoma in 51 (24.6%), and mixed adenocarcinoma-signet ring cell adenocarcinoma in 40 patients (19.2%). Of all 208 patients, HP was positive in 87 (41.8%) and negative in 121 (58.2%) patients. FISH positivity for HER2 was observed in 41 (19.7%), whereas FISH negativity was observed in 167 (80.3%) patients. According to the Chi-square test, patient distribution were 21 in HER2 positive HP negative group, 20 in HER2 positive HP positive group, 100 in HER2 negative HP negative group and 67 in HER2 negative HP positive group. No correlation was found between HP and HER2 status (p = 0.314). In addition, there was no relationship between HP status and the age, gender, histopathologic diagnosis, tumor location, TNM stage, ECOG performance status, grade, lymphovascular invasion, perineural invasion, and Lauren classification. Median OS of the entire population was 14.8 months (0.07-82.5). Median OS was 12.9 months (95% CI 7.7-18.0) in HP negative group and 27.4 months (95% CI 16.4-38.4) in HP positive group and the difference was statistically significant (p = 0.046).
Our results suggest that there is no relationship between HP infection and HER2 status in patients with GC. However, debate on this topic continues. Comprehensive prospective studies with larger series are required to clarify this relationship.
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All authors have declared no conflicts of interest.