GPR15 and lung adenocarcinoma: For lung adenocarcinoma, we found that the expression levels of three genes, GPR15, HDGF, and AHHR, were associated with increased smoking-related mutational signature, while an inverse association was observed for the other four genes, NWD1, KCNQ1, CAPN8 and RPS6KA1 (Fig. 1, Table 1).