Naive CD4+ T cells that receive tumor antigens through the MHC class II pathway and co-stimulatory signals from DCs differentiate into T helper 1 (Th1) cells, T helper 2 (Th2) cells, T helper 17 (Th17) cells or regulatory T (Treg) cells with the use of corresponding cytokines required for each CD4+ T cell subtype [29,30]. Here, CD4 is linked to neoplasm.