This gene encodes a heme enzyme that plays a critical role in tryptophan metabolism by catalyzing the first and rate-limiting step of the kynurenine pathway. Increased activity of the encoded protein and subsequent kynurenine production may also play a role in cancer through the suppression of antitumor immune responses, and single nucleotide polymorphisms in this gene may be associated with autism.,TDO2,TDO,TO,TPH2,TRPO,tryptophan 2,Cancer,Signal Transduction,Endocrine & Metabolism,Amino acid metabolism,TDO2