Additionally, we confirmed the role of AhR in Breg differentiation in lung cancer, by validating the upregulation of AhR expression in immune sorted CD19+ B cells from splenocytes of tumor-bearing WT compared to tumor-bearing IDO-/- and WT naïve (Figure 4C). L-Kyn is an endogenous ligand of cytoplasmic transcription factor AhR, which after binding with AhR makes AhR complex, translocates into the nucleus to bind further with AhR nuclear translocator (Arnt). This evidence concerns the gene CD19 and lung carcinoma.