OBJECTIVE To explore the correlation between phosphatidylinositol-3-kinase alpha (PIK3CA) gene mutation and the clinicopathological characteristics of Epstein-Barr virus (EBV) infection in patients with gastric cancer.
METHODS Cancer tissue samples were collected from 593 patients with gastric cancer who underwent surgery at the Affiliated Hospital of Hebei University between Sep. 2021 and Sep. 2024. EBV infection in patients with gastric cancer was detected by EBV-encoded RNA (EBER) in situ hybridization. Based on the detection results, patients were divided into an EBV-positive group (n=31) and an EBV-negative group (n=562). The incidence of EBV-infected gastric cancer was compared among patients of different genders and ages. The relationship between EBV infection and PIK3CA gene mutation, as well as clinicopathological characteristics of patients with gastric cancer, was analyzed. Spearman's correlation analysis was used to assess the correlation between PIK3CA gene mutation and EBV infection in patients with gastric cancer.
RESULTS Among the 593 gastric cancer cases, 31 were EBER-positive, with a positive rate of 5.23%. EBER showed scattered dot scope or diffuse staining, appearing as a dark brown signal localized in the nucleus. The PIK3CA gene mutation rate was higher in the EBV-positive group (32.26%) than in the EBV-negative group (P < 0.001). PIK3CA gene mutations mainly occurred in exons 9 and 20, with 2 cases of p.E542K mutation, 5 cases of p.E545K mutation, 1 case of pH1047L mutation, no cases of p.H1047R mutation were detected. The proportion of patients with tumors at the esophagogastric junction, T3-T4 invasion depth, and lymph node metastasis was higher in the EBV-positive group than in the EBV-negative group (P < 0.05). There was a positive correlation between PIK3CA gene mutation and EBV infection in patients with gastric cancer (r=0.742, P=0.026). The proportion of EBV infection was higher in male patients with gastric cancer (6.49%) than in females (P < 0.001).
CONCLUSIONS The incidence of EBV-infected gastric cancer is low, but it is closely related to PIK3CA gene mutation, gender, tumor location, invasion depth and lymph node metastasis in patients with gastric cancer.
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