# Notch-1/2 receptors and Jagged-1 ligand, but not HERP-1 transcription factor, are immunohistochemically expressed in the epithelial lining of periapical cysts

## TL;DR

This study found that Notch-1/2 and Jagged-1 are expressed in the lining of periapical cysts, but HERP-1 is not, suggesting the Notch signaling pathway may play a role in their development.

## Contribution

The study provides new evidence of Notch pathway activation in periapical cysts through immunohistochemical analysis.

## Key findings

- Notch-1 was expressed in all 30 periapical cysts, in both basal and suprabasal epithelial cells.
- HERP-1 was not detected in the lining epithelium of any cysts.
- No significant correlation was found between receptor/ligand expression and inflammation in the cystic wall.

## Abstract

To further understand the involvement of Notch pathway signaling in the pathogenesis of periapical cyst the immunohistochemical expression of Notch-1 and Notch-2 receptors, Jagged-1 ligand, and HERP-1 transcription factor in the lining epithelium of periapical cysts was investigated.

Thirty human periapical cysts were immunohistochemically stained with antibodies against Notch-1, Notch-2, Jagged-1, and HERP-1. Epithelial expression of each antibody was correlated with the presence of inflammation in the connective tissue of the cystic wall.

Notch-1 was identified in the basal and suprabasal epithelial cells of 30/30, Notch-2 in 19/24, and Jagged-1 in 27/30 cysts. HERP-1 was detected in scattered subepithelial inflammatory cells, but not in the lining epithelium of cysts. There was no significant correlation between the immunohistochemical expression of each antibody and the presence of inflammation in the connective tissue of the cystic wall.

This immunohistochemical study showed expression of Notch-1/2 and Jagged-1 in periapical cysts that combined with the expression of HES1/5 found in a previous report, are indicative of the activation of Notch an endocrine-paracrine mechanism. Further research on the activity of Notch and other pathways in periapical cysts may contribute both to elucidate their pathogenesis and select molecular targets for future novel treatments.

Key words:Odontogenic cyst, radicular cyst, etiology, epithelial cells, Notch, Jagged, HERP.