CD4 and neoplasm: Tumor-infiltrating immune cells include T-lymphocytes [CD8+ cytotoxic (memory) T-cells, CD4+ helper (Th1, Th2) T-cells, and regulatory T-cells (Tregs)], B lymphocytes (B-cells), tumor-associated macrophages (TAMs), tumor-associated neutrophils (TANs), myeloid-derived suppressor cells (MDSCs), dendritic cells (DCs), and natural killer (NK) cells (5, 6).