Association of B3GNT3 Expression with Tumour Stage and Lymph Node Metastasis in Colon Adenocarcinoma

Aberrant glycosylation contributes to tumour progression and metastatic dissemination. Beta-1,3-N-acetylglucosaminyltransferase 3 (B3GNT3) is involved in poly-N-acetyllactosamine synthesis, but its role in colon adenocarcinoma remains insufficiently characterised. This retrospective single-centre study evaluated B3GNT3 expression and its association with clinicopathological parameters using TCGA and CPTAC data, immunohistochemistry in 97 colon adenocarcinomas, Western blot analysis, and transmission electron microscopy. TCGA analysis showed no significant differences in B3GNT3 mRNA expression between normal and tumour tissues. In contrast, CPTAC, immunohistochemistry, and Western blot analyses demonstrated increased B3GNT3 protein expression in tumour tissue compared with non-neoplastic mucosa. Immunohistochemical expression was assessed semi-quantitatively using the immunoreactive score (IRS). Lower B3GNT3 expression was associated with advanced stage and node-positive status. Because pathological stage and lymph node status are interrelated clinicopathological variables in colon adenocarcinoma, these findings were interpreted as partially overlapping associations rather than independent biological endpoints. Exploratory ROC and logistic regression analyses supported these cohort-level associations; however, the ROC-derived IRS cut-off was not externally validated, and regression models were interpreted cautiously. TEM/immunogold analysis supported Golgi/secretory-pathway localisation but was descriptive. Overall, B3GNT3 expression was associated with clinicopathological features in this retrospective cohort.