CD4 and gastric cancer: The infiltrative lymphocytes, such as CD8+ cytotoxic T lymphocytes (CTLs), CD4 + T lymphocytes (Th1, Th2, Th17, and Tregs), natural killer cells (NKs), dendritic cells (DCs), macrophages, and B cells, are involved in the progression of GC [18, 19, 20, 21, 22, 23].