IDO2 and lung cancer: RNAseq data for the 7 lung cancer cell lines (Minna lab, dbGaP Study Accession phs001823.v1.p1), we determined that TDO2 mRNA was elevated in A549, H1792, H2347, and H2228 cells, while IDO1 and IDO2 were low in most cell lines (Fig. 1A).