# Expression of Epithelial-Mesenchymal Transition-Related Protein Claudin‐10 in Oral Lichen Planus

## TL;DR

This study investigates the expression of Claudin-10, an EMT-related protein, in oral lichen planus and finds it is significantly altered compared to normal oral mucosa.

## Contribution

This is the first study to describe Claudin-10 immunohistological expression in oral mucosal disease.

## Key findings

- Claudin-10 expression is significantly enhanced in OLP epithelium compared to controls.
- Staining in superficial and stromal layers is stronger in OLP, while intermediate and basal layers show reduced staining.

## Abstract

Introduction: Oral lichen planus (OLP) is a common skin disease of indeterminate etiology that can affect the oral mucosa. Epithelial-mesenchymal transition (EMT) is a critical biological event that plays an essential role in several functions, such as development, tissue repair, and stem cell dynamics, but also in cancer progression. Claudin-10, an EMT-related protein, is encoded by the CLDN10 gene in humans. In the present work, we studied the immunohistological expression of Claudin-10 in OLP compared to normal oral mucosa.

Methods: Fifty-one formalin‐fixed, paraffin‐embedded samples diagnosed as OLP from patients who did not receive any medications for the treatment of OLP until the initial biopsy and ten formalin-fixed, paraffin‐embedded samples diagnosed as comprising histologically normal oral mucosa tissue from resection margins of fibromas were immunohistochemically stained and analyzed for Claudin-10.

Results: The expression of Claudin‐10 was evaluated as significantly enhanced in OLP epithelium compared to controls (p<0.001). In the superficial epithelial layer, the staining was markedly higher in OLP than in the controls (p=0.008), and in the stroma, the staining was significantly stronger in OLP (p=0.027). In the intermediate epithelial layer, the staining was significantly weaker in OLP than in the controls (p=0.001), and in the basal layer, the staining was markedly reduced in OLP (p<0.001).

Conclusions: The immunohistological expression of Claudin‐10 has been described and analyzed in oral mucosal disease for the first time. Our findings indicate that the expression of Claudin‐10 is dysregulated in OLP, possibly showing an interaction between the epithelium and the underlying tissue.