Fig. 1

Identification of genes and their associations with smoking-related mutational signature. a A flow chart to illustrate the identification of candidate smoking-related DNA methylations from the previously reported blood-based methylations in five EWAS. “N” represents the sample size for each study. b Smoking-related mutational signature displayed according to the 96 substitution classifications characterized by six substitution types, together with a flanking base pair to the mutated base (Alexandrov et al. 2013). c A scatter plot indicating tobacco smoking correlated with known smoking-related mutational signature in lung adenocarcinoma. The dotted line refers to association coefficient. Each point represents one sample. The x axis represents the number of packs per year for each sample, the y axis represents the contribution of smoking-related mutational signature to overall mutation burden for each sample. The color from red to green refers to a higher to lower density of samples (this note applies to all other figure legends). d Box plots of the enrichment score of smoking-related mutational signature across 26 cancer types. e Bar plots indicating the P value of associations between the candidate genes and smoking-related mutational signature in six cancer types. Only genes with a P value of less than 1 × 10^− 4 were presented. The dashed dot box highlights the genes with significant associations at a Bonferroni-correction P < 0.001. f Scatter plots for each gene with significant associations at a Bonferroni-correction P < 0.001. From the left to the right panel, four genes in head and neck and seven genes in lung adenocarcinoma are presented