CD4 and cancer: Based on the critical role of CD4 Th1 cells in antitumor immunity, we believe that effectiveness of cancer vaccine could be greatly enhanced by stimulating suitable tumor-reactive Th1 immunity, making a “good” tumor microenvironment for the immune effector cells action (CD8 T cells, NK cells and M1 macrophages) and a “bad” one for the immune suppressive cells (Tregs, MDSC, etc.).