STAT3 and liver cancer: Another study demonstrated that TDO2-Kyn-AhR activation in liver cancer cells induces autocrine interleukin 6 (IL-6)-mediated Signal transducer and activator of transcription 3 (STAT3) and Nuclear factor kappa beta (NFκB)/T Cell Immunoglobulin And Mucin Domain Containing 4 (TIM4) signaling to promote tumor progression (68).