PIK3CA and nasopharyngeal type undifferentiated carcinoma: For intestinal/solid type GC patients, EBV-positive tumors were associated with greater PD-L1 expression and more liver metastases than EBV-negative tumors; for lymphoepithelioma-like GC patients, EBV-positive tumors were associated with more PI3K/AKT pathway mutations than EBV-negative tumors.