Fig. 4

Increased numbers of differentially expressed genes in the sputum of cigarettes smokers vs. e-cigarette users. (A) Heatmap showing significant (log2 fold change |≥1 and p≤ 0.005) combined genes from pairwise comparisons in sputum (cigarette smokers, Cig; e-cigarette users, E-cigs; and controls, Cont). (B, C and E) Volcano plots of DEGs in sputum from pairwise comparisons between (B) e-cigarette users (E-cigs) and controls, (C) cigarette smokers and controls, and (E) cigarette smokers and E-cigarette users (E-cigs). (D) Venn diagram representing the number of DEGs that overlap between each comparison