# Immunohistochemical Analysis of CD117 in the Mast Cells of Odontogenic Keratocysts

## TL;DR

This study uses CD117 to analyze mast cells in odontogenic keratocysts and finds higher mast cell counts in recurrent cases, suggesting a link to aggressive behavior.

## Contribution

The study introduces a novel immunohistochemical analysis of mast cells in different subtypes of odontogenic keratocysts using CD117.

## Key findings

- Recurrent OKCs showed significantly increased mast cells in subepithelial and deep connective tissue (p < 0.05).
- Syndromic OKCs had increased mast cell counts in the deep connective tissue layer.
- No significant differences in mast cell counts were found among the three OKC subtypes overall.

## Abstract

Background: Odontogenic lesions contain mast cells (MCs), particularly those with a cystic appearance. Because of their high recurrence rates and aggressive clinical behaviour, odontogenic keratocysts (OKCs) require special treatment. A particular kind of protein called cluster of differentiation (CD) 117/ receptor tyrosine kinase (c-KIT) is present on the surface of many cells. Most hematopoietic cells lose their expression of KIT during the differentiation process, with the exception of MCs, which continue to express KIT throughout their lifetime.

Aim: Using the CD117 immunomarker, this immunohistochemical investigation sought to assess the presence and location of MCs in OKCs and examine the relationship between MC numbers in sporadic, syndromic, and recurrent OKCs.

Methods: The study comprised 30 paraffin-embedded tissue specimens, and a histopathological diagnosis was made from hematoxylin and eosin-stained sections with a thickness of 4-5 µ. Out of 30 specimens, 21 were sporadic, six were recurrent OKCs, and three were syndrome-associated OKCs. CD-117/c-kit rabbit polyclonal primary antibody was used to stain the sections for observing MCs, which were then viewed under a light microscope with a digital camera and a desktop computer with MICAPS software for viewing images.

Result: To compare the number of MCs among OKCs, a one-way ANOVA test was used. Our study revealed that a statistically significant increase in MCs has been observed in the subepithelial and deep connective tissue of recurrent OKC (p < 0.05). However, a comparison of the mean MC value among three OKC subtypes did not reveal any statistically significant differences. An increased mast count was observed in the deep connective tissue layer of syndromic OKC under multiple comparisons.

Conclusion: Our study concluded that MCs were present in increased numbers both in the superficial and deep connective tissue of recurrent OKCs, indicative of their aggressive clinical behaviour. Increased mean MC counts observed in some of the sporadic cases may be an indicator of their chances of recurrence in the future.