Immunohistochemical expression of CANT1 and B3GNT3 in invasive ductal carcinoma of the breast: diagnostic and prognostic significance in lymph node metastasis.

[BACKGROUND] Breast cancer is a leading global health concern, with lymph node metastasis (LNM) being a key prognostic factor affecting patient outcomes. Glycosylation-related enzymes such as calcium-activated nucleotidase 1 (CANT1) and Beta-1,3-N-acetylglucosaminyltransferase 3 (B3GNT3) have been implicated in tumour progression, yet their roles in breast cancer, particularly invasive ductal carcinoma (IDC), are not well defined. This study investigates the immunohistochemical expression and correlation of CANT1 and B3GNT3 in IDC and their potential role in predicting LNM and clinical outcomes.

[MATERIALS AND METHODS] Slides from paraffin blocks of 140 IDC cases and 108 corresponding metastatic axillary lymph nodes were stained with CANT1 and B3GNT3 antibodies. Associations between markers' immunoreactivity and clinicopathological variables were evaluated. Progression-free survival (PFS) was analysed using the Kaplan-Meier method. The prognostic significance of each variable was evaluated using both univariate and multivariate Cox proportional hazards regression analyses.

[RESULTS] High CANT1 and B3GNT3 expression was observed in 47.1% and 45.7% of cases, respectively. Both markers were significantly associated with tumour grade, tumour stage, Nottingham prognostic index, lymph node status, lymph node ratio, Her2 status, Ki-67 proliferative index and distant metastasis. A significant positive correlation was found between CANT1 and B3GNT3 expression (p < 0.001). Co-expression of both markers was strongly associated with LNM, along with a significant difference in the expression levels of each marker between primary tumours and corresponding LNM. Univariate analysis showed that tumour grade, stage, ER status and high B3GNT3 expression were all significantly associated with worse PFS. Multivariate Cox regression identified B3GNT3 expression, tumour grade and tumour stage as independent predictors of poor prognosis in IDC. High expression levels of CANT1 and B3GNT3 were associated with reduced PFS across all IDC cases (p = 0.035 and p = 0.001, respectively).

[CONCLUSIONS] High CANT1 and B3GNT3 expressions are associated with aggressive clinicopathological features in IDC and predict unfavourable outcomes. These markers may serve as potential prognostic indicators and independent predictors of LNM in IDC patients.