Molecular profiling of oral epithelial dysplasia and oral squamous cell carcinoma using next generation sequencing.

Abstract

Background: Next generation sequencing (NGS) is a massive, high-throughput sequencing technology used to analyze various mutations and genetic changes in cancer. Oral squamous cell carcinoma (OSCC) is the most common malignancy of the head and neck region. OSCC usually arises from oral potentially malignant disorders, like oral leukoplakia, oral submucous fibrosis and erythroplakia, and shows mutation of tumor suppressor genes, and several other critical genes involved in apoptotic pathways, cell migration, and cell growth.

Aim: To analyze the molecular profiles of oral epithelial dysplasia and different grades of oral squamous cell carcinoma using NGS in the Indian subpopulation.

Methodology: 21 patients (5 patients each of well differentiated, moderately differentiated, poorly differentiated squamous cell carcinoma, severe epithelial dysplasia, and 1 normal appearing mucosal tissue from apparently healthy individuals) were included in the study. Next generation sequencing was carried out using 50 hotspot gene panel. Protein-protein analysis was carried out using STRING Consortium 2023 and the methylation profile of the expressed genes was evaluated using the UALCAN portal.

Results: Severe epithelial dysplasia showed TP53 (c.743G>A, p.R248Q) pathogenic mutations (SNV) in suboptimal QC parameters. Well differentiated squamous cell carcinoma showed TP53 (c.328delC, p.Arg110fs*13), APC (c.4135G>T, p.Glu1379*), and FBXW7 (c.832C>T, p.Arg278*) mutations. CTNNB1 (c.134C>T, p.Ser45PheS45F), TP53 (c.637C>T, Arg213TerR213*), NRAS (c.183A>C, p.Gln61HisQ61H) and PDGFRA (c.1672C>T, p.Arg558Cys) mutations were seen in moderately differentiated squamous cell carcinoma. No pathogenic mutations were evident in poorly differentiated squamous cell carcinoma. STRING analysis showed that all the expressed proteins in each group were interrelated to each other. No significant difference was evident in the methylation profile of all the expressed genes when compared to the normal controls.

Conclusion: The results obtained in this study explain the diverse genetic mutations in various grades of oral squamous cell carcinoma. Identification of these mutations would help in providing better treatment, designing a proper treatment plan for the patients with OSCC and support minimal intervention medicine.