CD4 and cancer: Among the up-regulated proteins in cells were TMSB4X, which sequesters actin monomers, thus inhibiting actin polymerization [38], EZR, a cytoplasmic peripheral membrane protein which serves as a linker between the plasma membrane and the actin cytoskeleton [39], XAGE1, a testis cancer antigen characterized by a strong immunogenicity able to induce CD4 and CD8 T lymphocyte responses in cancer [40], and the HLA class I histocompatibility antigen, A alpha chain, which is involved in the presentation of intracellular antigens by tumor-specific cytotoxic CD8 T lymphocytes [41].