Thus, tumor-derived immunosuppressive factors, such as vascular endothelial growth factor [58, 59], PGE-2[54], spermine [6], and mechanisms such as apoptosis of DC and T cells [60, 61], Fas/FasL interaction [62], TLR-4 mediated resistance of tumor cells to CTL attack [63], as well as defective maturation of hematopoetic cells [64] may obstruct effective in vivo immune responses by inhibiting endogenous DC function. This evidence concerns the gene FAS and neoplasm.