Analysis of clinicopathological and molecular characteristics of EBV-associated gastric cancer.

OBJECTIVE: This study aims to explore the clinicopathological and molecular traits of Epstein-Barr virus-associated gastric cancer (EBV-GC). METHODS: A retrospective analysis was performed on the clinicopathological features, immunophenotype, and molecular characteristics of seven EBV-GC cases utilizing next-generation sequencing (NGS) technology. RESULTS: Among the seven cases, six were male and one was female, aged from 24 to 76 years (mean age: 56 years). Tumor sizes varied between 10 and 100 mm (mean size: 54.2 mm). The tumors were mainly located in the upper and middle regions of the stomach, predominantly exhibiting an ulcerative appearance. Numerous cases were linked with gastric carcinoma with lymphoid stroma. About half of the cases were identified as diffuse type according to the Lauren classification. All cases were in the early stage, with lymph node metastasis being uncommon. Immunophenotyping demonstrated positive Epstein-Barr virus-encoded RNA, common overexpression of programmed death-ligand one, and presence of tumor-infiltrating lymphocytes. Human epidermal growth factor receptor 2 (HER2) and microsatellite instability were negative. The molecular characteristics frequently included PIK3CA and ARID1A mutations, whereas TP53, HER2, EGFR mutations, and deficient mismatch repair were absent. CONCLUSION: EBV-GC is characterized by distinct clinicopathological and molecular features. Pathological examination, immunophenotyping, and NGS provide significant value for diagnosis and therapeutic direction.