# Prognostic Impact of Mucin Expression in Curatively Resected Ampulla of Vater Cancer

## TL;DR

This study finds that MUC5AC expression in ampulla of Vater cancer is linked to worse survival and lymph node spread, suggesting it could guide treatment decisions.

## Contribution

The study identifies MUC5AC as a novel prognostic biomarker for ampulla of Vater cancer, independent of histological subtype.

## Key findings

- MUC5AC expression correlates with lymph node metastasis in ampulla of Vater cancer.
- MUC5AC is a significant predictor of overall survival in these patients.
- MUC5AC expression is not associated with recurrence-free survival.

## Abstract

It is generally reported that the prognostic factors for ampulla of Vater cancer include T stage, N stage, and lymphovascular invasion and subtype, and the meaning of MUC stain is controversial. This retrospective study by the authors evaluated the significance of various MUC stains in AoV cancer using single-center clinicopathological data. The results showed that MUC5AC was significant for lymph node metastasis and was furthermore valuable as a prognostic factor for predicting overall survival. If this is evaluated in addition to the hematoxylin and eosin stain, which is commonly performed in preoperative biopsy, it is expected to be a method to select groups that require more extensive LN dissection and further prevent locoregional recurrence.

Introduction: Mucins play a pivotal role in epithelial carcinogenesis; however, their role remains elusive in ampulla of Vater (AoV) cancer, regardless of histological subtype. Therefore, we investigated the clinical significance of MUC1, MUC2, MUC5AC, and MUC6 expression in AoV cancer. Methods: Using samples from 68 patients with AoV cancer, we performed immunohistochemical staining for MUC1, MUC2, MUC5AC, and MUC6 using a tissue microarray. Subsequently, we analyzed their expression patterns in relation to clinicopathological parameters and patient outcomes. Results: Of the patients, 98.5% exhibited positive expression for MUC1, while MUC2, MUC5AC, and MUC6 were expressed in 44.1%, 47.1%, and 41.2% of the patients, respectively. Correlation analyses between mucin expression and clinicopathological factors revealed no significant associations, except between MUC5AC expression and N stage. Univariate analysis demonstrated significant associations between MUC5AC expression and overall survival (OS). Multivariate analysis further confirmed that MUC5AC expression was a significant predictor of OS, along with the N stage. However, MUC5AC expression was not meaningfully associated with recurrence-free survival (RFS). The patients positive for MUC5AC expression had a considerably shorter OS than those with negative expression. Conclusions: Our study provides insights into the clinical impact of mucins on AoV cancer, regardless of the histological subtype. Although MUC1 expression is universal, MUC5AC expression is a significant prognostic indicator that correlates with lymph node metastasis and poor OS. These results emphasize the possible utility of MUC5AC as a biomarker for extensive lymph node dissection and the prognostic evaluation of patients with AoV cancer.