RNA-Sequencing of the Microenvironment of Oral Potentially Malignant Disorders

Abstract

Introduction

the persistent issue in the diagnostic separation between OLP and OED is the considerable clinical and histologic overlap between the two entities. The differentiation is currently based on relatively subjective evaluation of the histological findings by the examining pathologist taking into account the clinical presentation. Although direct immunofluorescence studies can help diagnose OLP, DIF has to be correlated with the appropriate clinical presentation and permanent sections, as basement membrane fibrinogen deposition is not pathognomonic of OLP and has been described in OED specimens and other mimickers. Thus, discrimination of OED associated with chronic interface mucositis from OLP with reactive cellular atypia can be challenging, requiring subjective assessment of ostensibly objective morphologic features.

Materials and Methods

We performed bulk RNA sequencing on all the samples to evaluate genetic markers previously described in tumor-infiltrating immune cells and compare between groups. Gene ontology and enrichment analysis were performed to explore the function and product of differential gene expressions in both study groups. The p-value of <0.05 and fold change >1.3 was set for this purpose, utilizing the Gene Ontology knowledgebase by the Gene Ontology Consortium (release date 2023-01-05).

Results

Functional analysis revealed enrichment of immune signatures associated with immunosurveillance, lymphocyte infiltration, cytotoxic response, and surrogate markers of tumor-associated macrophages in high-grade OED. In OLP, our data revealed differential gene expression mainly related to cell regulation process, lymphocyte infiltration, and pathways related to T-cell regulation.

Conclusions

Immune reactivity is prominent in both epithelial and connective tissue components of OED and OLP. Nonetheless, our data suggests that the phenotype and genetic markers in the immune component are different. Further studies, including more cases and single-cell RNA sequencing, are necessary to substantiate these findings.