Comprehensive serum proteomics profiles and potential protein biomarkers for the early detection of advanced adenoma and colorectal cancer

Figure 1 Partial least squares discrimination analysis plot, volcano plot, and heatmap between the normal control group and advanced adenoma group. A: Partial least squares discrimination analysis shows the protein expression in the normal control group (blue) and advanced adenoma group (green); B: Volcano plot shows the fold change of the identified proteins between the two groups; C: Hierarchical clustering analysis shows the upregulated (red) and downregulated (green) differentially expressed proteins between the two groups. NC: Normal control; AA: Advanced adenoma; PLS-DA: Partial least squares discrimination analysis.

Figure 2 Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes enrichment analysis of differentially expressed protein between the normal control group and advanced adenoma group. A: Gene Ontology enrichment analysis: differentially expressed proteins (DEPs) are mainly enriched in fatty acid metabolism process, cell adhesion molecule binding, and vesicle lumen; B: Kyoto Encyclopedia of Genes and Genomes enrichment analysis: DEPs are mainly enriched in metabolic pathways and ribosomes. NC: Normal control; AA: Advanced adenoma; DEPs: Differentially expressed proteins; GO: Gene Ontology; KEGG: Kyoto Encyclopedia of Genes and Genomes.

Figure 3 Partial least squares discrimination analysis plot, volcano plot, and heatmap between the normal control group and colorectal cancer group. A: Partial least squares discrimination analysis shows the protein expression in the normal control group (blue) and colorectal cancer group (orange); B: Volcano plot shows the fold change of the identified proteins between the two groups; C: Hierarchical clustering analysis shows the upregulated (red) and downregulated (green) partial least squares discrimination analysis between the two groups. NC: Normal control; CRC: Colorectal cancer; PLS-DA: Partial least squares discrimination analysis.

Figure 4 Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes enrichment analysis of differentially expressed proteins between the normal control group and colorectal cancer group. A: Gene Ontology enrichment analysis: Differentially expressed proteins (DEPs) are mainly enriched in amide biosynthetic process, protein binding, and secretory granule lumen; B: Kyoto Encyclopedia of Genes and Genomes enrichment analysis: DEPs are mainly enriched in metabolic pathways, ribosomes, and endocytosis. NC: Normal control; CRC: Colorectal cancer; DEPs: Differentially expressed proteins; GO: Gene Ontology; KEGG: Kyoto Encyclopedia of Genes and Genomes.

Figure 5 Partial least squares discrimination analysis plot, volcano plot, and heatmap between the advanced adenoma group and colorectal cancer group. A: Partial least squares discrimination analysis shows the protein expression in the advanced adenoma group (green) and colorectal cancer group (orange); B: Volcano plot shows the fold change of the identified proteins between the two groups; C: Hierarchical clustering analysis shows the upregulated (red) and downregulated (green) differentially expressed proteins between the two groups. AA: Advanced adenoma; CRC: Colorectal cancer; PLS-DA: Partial least squares discrimination analysis.

Figure 6 Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes enrichment analysis of differentially expressed proteins between the advanced adenoma group and colorectal cancer group. A: Gene Ontology enrichment analysis: Differentially expressed proteins (DEPs) are mainly enriched in amide biosynthetic process, protein binding, and extracellular exosome; B: Kyoto Encyclopedia of Genes and Genomes enrichment analysis: DEPs are mainly enriched in metabolic pathways, ribosomes, and PPAR signaling pathway. AA: Advanced adenoma; CRC: Colorectal cancer; DEPs: Differentially expressed proteins; GO: Gene Ontology; KEGG: Kyoto Encyclopedia of Genes and Genomes.

Figure 7 Intersecting differentially expressed proteins of the normal control, advanced adenoma, and colorectal cancer groups and serum relative protein level of seven biomarkers. A: Venn diagram indicates the intersecting differentially expressed proteins of the normal control (NC), advanced adenoma (AA), and colorectal cancer (CRC) groups; B-H: Serum relative protein level of DIAPH1, VASP, RAB11B, LBP, SAR1A, TUBGCP5, and DOK3 in NC, AA, CRC groups. DEPs: Differentially expressed proteins; NC: Normal control; AA: Advanced adenoma; CRC: Colorectal cancer.

Figure 8 The relationship between seven protein biomarkers and 5-year overall survival in colorectal cancer patients. Patients with high expression of VASP, LBP, TUBGCP5, and DOK3 had significantly lower overall survival rates. OS: Overall survival; CRC: Colorectal cancer.

Figure 9 Immunohistochemical staining of LBP protein and VASP protein (200 ×). A-C: LBP is not expressed in normal colon tissues, while highly expressed in advanced adenoma (AA) tissues and colorectal cancer (CRC) tissues; D: Expression levels of LBP protein among the three groups; E-G: VASP is not expressed in normal colon tissues, while highly expressed in AA tissues and CRC tissues; H: Expression levels of VASP protein among the three groups. AA: Advanced adenoma; CRC: Colorectal cancer; AOD: Average optical density; NC: Normal control.