Comprehensive proteomic signature and identification of CDKN2A as a promising prognostic biomarker and therapeutic target of colorectal cancer

Figure 1 Quantitative proteomic profiling and bioinformatic analysis of colorectal cancer. A: Partial least squares-discriminant analysis of colorectal cancer and normal tissues; B: The volcano plot shows 1115 upregulated and 705 downregulated proteins in tumors; C: Gene ontology analysis shows that differentially expressed proteins are involved in biological processes, cellular components, and molecular functions; D: Kyoto encyclopedia of genes and genomes analysis shows that differentially expressed proteins are significantly enriched in multiple pathways including ribosome biogenesis in eukaryotes, focal adhesion, cell cycle and extracellular matrix-receptor interaction; E and F: Gene set enrichment analysis shows that differentially expressed proteins are enriched in the cell cycle and p53 signaling pathway. PLS-DA: Partial least squares-discriminant analysis; CRC: Colorectal cancer tissue; CN: Normal colon tissue; GO: Gene ontology; KEGG: Kyoto encyclopedia of genes and genomes; ECM: Extracellular matrix; NES: Normalized enrichment score.

Figure 2 Immunohistochemical validation of cyclin-dependent kinase inhibitor 2A and overall survival analysis. A: Immunohistochemical images showing cyclin-dependent kinase inhibitor 2A (CDKN2A) negativity in normal colon tissues and CDKN2A positivity in colorectal cancer (CRC) tissues; B: Comparison of CDKN2A expression in CRC and normal tissues based on the average option density (AOD). AOD calculated using ImageJ software; C: GEPIA shows gene overexpression of CDKN2A in both colon adenocarcinoma and rectum adenocarcinoma patients in comparison with normal people; D: The relationship between CDKN2A expression and overall survival in CRC patients. Patients with high CDKN2A expression have a poor prognosis, and those with low CDKN2A expression have a longer survival time. CRC: Colorectal cancer; AOD: Average option density; COAD: Colon adenocarcinoma; READ: Rectum adenocarcinoma; CDKN2A: Cyclin-dependent kinase inhibitor 2A.