IDO1 and cancer: While PGE-2 induces blood vessel dilatation and inflammation, COX2 expression by the cancer cells was shown to inhibit T cell accumulation in the tumor mass, to favor immunosuppressive myeloid cell polarization, to impair DC and NK cell functions and to drive the expression of the indoleamine 2,3-dioxygenase-1 (IDO-1) [for review see (80)].