Activation of aryl hydrocarbon receptor promotes invasion of clear cell renal cell carcinoma and is associated with poor prognosis and cigarette smoke, Kynurenine, the endogenous ligand of the AHR, could either activate triple-negative breast cancer cell migration [12] or inhibit neuroblastoma cell migration to activate AHR [13]. The gene discussed is AHR; the disease is clear cell renal carcinoma.