Fig. 4

a Gene ontology (GO) analysis on differentially expressed proteins (Top 20). Bar chart color represent P value based on Fisher’s Exact Test, the closer the color is to red, the smaller the P value is. BP, biological process; MF, molecular function; CC, cellular component. b KEGG analysis differentially expressed proteins (Top 20). c KEGG analysis of differentially expressed proteins shows significantly differences in cysteine and methionine metabolism, and small cell lung cancer related pathway. d UHPLC-Obitrap MS BPC for three runs of quality control samples shows high precision. e PCA analysis shows a good experimental repeatability