As shown in Figure 1, cancer cells may target a number of factors that act to regulate the mitochondrial melatonergic pathway in tumor microenvironment cells, including tryptophan uptake, 14-3-3 isoforms, TPH1/2, serotonin uptake/metabolism, acetyl-CoA, AANAT, ASMT, P2Y1r and mGluR5 receptor, as well as the AhR. Here, AHR is linked to cancer.