Downregulation of B3GNT6 Predicts Poor Outcome in Colorectal Cancer Patients

Abstract Background: B3GNT6 encodes the core 3 synthase in O-glycan biosynthesis. It is commonly expressed in the GI tract, while its clinical significance in colorectal cancer remains largely unknown.Methods: We gathered mRNA transcriptomic sequencing data from 3 Gene Expression Omnibus (GEO) datasets (GSE37182, GSE39582, GSE103512) and The Cancer Genome Atlas (TCGA) to compare the B3GNT6 mRNA level between colorectal cancer tissues and normal tissues and to evaluate its value as a prognostic marker. We further validated this in protein level using online database Human Protein Atlas and with immunohistochemical staining of B3GNT6 with our own cohort. Results: B3GNT6 expression was downregulated in colorectal cancer tissue compared with that in normal tissue in both mRNA and in protein level. Downregulation of B3GNT6 was associated with poor overall survival of colorectal cancer in GSE39582 and in TCGA database. Low B3GNT6 mRNA level was significantly associated with chromosome stable (CIN negative) and KRAS mutated group colorectal cancer patient. GSEA revealed that low B3GNT6 level in colorectal cancer is associated with upregulated proteasome activity.Conclusions: Downregulated B3GNT6 was correlated with poor overall survival of colorectal cancer patients. B3GNT6 could be used as a good prognostic marker in colorectal cancer.