Noncoding RNAs-based high KIF26B expression correlates with poor prognosis and tumor immune infiltration in colon cancer

BACKGROUND: The protein kinesin family member 26B (KIF26B) is aberrantly expressed in various cancers. However, its particular role and association with tumor immune infiltration in colon adenocarcinoma (COAD) remain unclear. METHODS: All original data were downloaded directly from The Cancer Genome Atlas (TCGA), UCSC Xena, and Gene Expression Omnibus (GEO) databases and processed with R 3.6.3. KIF26B expression was analyzed using Oncomine, TIMER, TCGA, GEO databases, and our clinical specimens. KIF26B expression at the protein level was explored with Human Protein Atlas (HPA) database. The upstream miRNAs and lncRNAs were predicted by StarBase and validated using RT-qPCR. Correlation of KIF26B expression with the expression of immune-related or immune checkpoint genes and GSEA analysis of KIF26B-related genes were investigated via R software. Relationship of KIF26B expression with immune biomarkers or tumor immune infiltration levels was studied through GEPIA2 and TIMER databases. RESULTS: KIF26B was upregulated, and its overexpression was closely related to overall survival (OS), disease-specific survival (DSS), progression-free interval (PFI), T stage, N stage, and CEA levels in COAD. MIR4435-2HG/hsa-miR−500a−3p/KIF26B axis was identified as the promising regulatory pathway of KIF26B. KIF26B expression was positively correlated with immune-related genes, tumor immune infiltration, and biomarker genes of immune cells in COAD, and KIF26B-related genes were significantly enriched in macrophage activation-related pathways. Expression of immune checkpoint genes, including PDCD1, CD274, and CTLA4, was also closely related to KIF26B expression. CONCLUSIONS: Our results clarified that ncRNA-based increased KIF26B expression was associated with a worse prognosis and high tumor immune infiltration in COAD.