IDO1 and breast neoplasm: Once breast tumors had developed in these mice, we treated them with the MUC1 vaccine in combination with a COX-1 and COX-2 inhibitor (indomethacin), a specific COX-2 inhibitor (celecoxib), an IDO inhibitor (1-MT) and a PGE2 receptor antagonist (AH6809) [45].