Notably, the regulatory role of NF-κB extends to the expression of KYN pathway genes and AhR, which is an endogenous KYN receptor, in triple-negative breast cancer (TNBC), suggesting that NF-κB activity positively regulates the expression of key genes related to tryptophan catabolism, making inhibitors of tryptophan 2,3-dioxygenase (TDO2) an attractive therapy for treating TNBC (68). The gene discussed is TDO2; the disease is triple-negative breast carcinoma.