Prognostic and immune infiltrates for the Chromobox (CBX) protein family in human pancreatic adenocarcinoma.

Background Globally, pancreatic adenocarcinoma (PAAD) is among the most prevalent malignant tumors. The Chromobox (CBX) protein family is a vital component of epigenetic regulatory complexes that have vital biological roles. The biological functions, immune infiltration, expression levels, and the prognostic significance of CBX proteins in PAAD have not yet been established. Methods Using bioinformatics tools, such as the Gene Expression Profiling Interactive Analysis (GEPIA), Oncomine, Kaplan-Meier plotter, GeneMANIA, cBioPortal, TIMER and R, we evaluated the prognostic importance, expression levels, gene alterations, risk factors, and immune cell infiltration levels of CBXs in PAAD patients. The expression levels of CBX3 in clinical-pathological samples were also confirmed by immunohistochemistry. Results In PAAD tissues, CBX1, CBX3, CBX5, and CBX8 expressions were high. High CBX1, CBX5, CBX6, and CBX7 levels were correlated with tumor stages. Elevated CBX2, CBX6, CBX7, and CBX8 messenger ribonucleic acid (mRNA) levels were markedly correlated with better overall survival (OS) outcomes for pancreatic cancer patients, while elevated CBX3 was markedly correlated with short OS outcomes. In particular, we have validated the differential expression of CBX3 on clinical specimens using immunohistochemical methods. A multivariate logistic analysis revealed that elevated mRNA expression levels of CBX3 and suppressed CBX8 levels were independently associated with short OS outcomes for pancreatic cancer patients. The roles of CBXs and their neighboring proteins are associated with a negatively regulated cell cycle, histone binding, polycomb group protein complexes, and the regulation of pluripotent stem cell signaling pathways. Additionally, CBX levels were found to be markedly associated with immune infiltrates, and found that the immune infiltration score of CBX3 was differentially expressed in cell lines such as CD8 T cells, NK cells, Mast cells and T helper cells. Conclusions CBX3/8 is a potential marker for prognostic outcomes in PAAD patients.