Hypothetically, the IFN-γ-STAT1 signaling induces apoptosis in proliferating tumor cells; however, TRCs-induced overexpression of IDO1 and AhR, shifts IFN-γ action and give rise to IDO1/AhR-induced p27 activation and inhibition of STAT1 signaling. The gene discussed is IDO1; the disease is neoplasm.