Fig. 2

Identification of smoking-related genes in lung cancer. a A volcano plot was generated to visualize the distribution of DEGs. b Counts of upregulated or downregulated mRNAs. Volcano plots were generated to visualize the distribution of DEGs between LUAD tissues and adjacent normal tissues from different study cohorts, including GSE27262 (c), GSE19804 (d), GSE19188 (e) and GSE76760 (f). The X-axis of volcano plot indicates the fold change (FC, log-scaled), whereas the Y-axis shows the p-values (log-scaled). Each dot represents a different gene, and the red/green color of the dots categorizes the up-regulated/down-regulated genes under the filtering condition. g Heatmap of DEGs derived from integrated analysis. Each column represents one dataset and each row represents one gene; the gradual color ranged from green to red represents the changing process from down-regulation to up-regulation. h Venn diagram showing the overlap of identified DEGs from GEO datasets and cigarette smoke-induced malignant-transformation-cell model