IDO1 and neoplasm: For example, Ido1 (indoleamine 2,3-dioxygenase 1) is the first and rate-limiting step in tryptophan catabolism and plays a role in antimicrobial and anti-tumor defense, neuropathology and immunoregulation, Casp3 (caspase 3) is a key executor of apoptosis and Lgals3 (galectin 3) plays a role in innate immunity and T-cell regulation and exhibits antimicrobial activity against bacteria and fungi.