AHR and hepatocellular carcinoma: Further examples for an impact of AHR activation on the signal transduction network, are the TCDD-induced phosphorylation of p38 MAPK observed in hepatoma cells (Weiss et al., 2005) and macrophages (Park et al., 2005), as well as the activation of EGFR and downstream ERK1/2 signaling by the AHR agonists 6-formylindolo[3,2-b]carbazole and TCDD in keratinocytes and colon cancer cells, respectively (Fritsche et al., 2007; Xie et al., 2012).