IDO1 and neoplasm: In addition, this suppression was restored by indoleamine 2,3-dioxygenase (IDO) or/and PGE2 inhibitors.4 It was reported that macrophage recruitment into tumors was induced by CAF-produced CCL25 and CXCL146 or by CAF-derived extracellular matrix modification,7 which resulted in enhanced tumor metastasis.