Biochemical analysis of cytokeratin fragment 21-1 concentration and expression of cytokeratin 19 in oral potentially malignant disorders

Shaping the future of oral cancer diagnosis: advances in salivary proteomics

INTRODUCTION

Saliva has gained increasing attention in the quest for disease biomarkers. Because it is a biological fluid that can be collected is an easy, painless, and safe way, it has been increasingly studied for the identification of oral cancer biomarkers. This is particularly important because oral cancer is often diagnosed at late stages with a poor prognosis.

AREAS COVERED

The review addresses the evolution of the experimental approaches used in salivary proteomics studies of oral cancer over the years and outlines advantages and pitfalls related to each one. In addition, examines the current landscape of oral cancer biomarker discovery and translation focusing on salivary proteomic studies. This discussion is based on an extensive literature search (PubMed, Scopus and Google Scholar).

EXPERT OPINION

The introduction of mass spectrometry has revolutionized the study of salivary proteomics. In the future, the focus will be on refining existing methods and introducing powerful experimental techniques such as mass spectrometry with selected reaction monitoring, which, despite their effectiveness, are still underutilized due to their high cost. In addition, conducting studies with larger cohorts and establishing standardized protocols for salivary proteomics are key challenges that need to be addressed in the coming years.

Salivary Biomarkers for Oral Cancer Detection: An Exploratory Systematic Review

Different efforts have been made to find better and less invasive methods for the diagnosis and prediction of oral cancer, such as the study of saliva as a source of biomarkers. The aim of this study was to perform a scoping review about salivary molecules that have been assessed as possible biomarkers for the diagnosis of oral squamous cell carcinoma (OSCC). A search was conducted using EBSCO, PubMed (MEDLINE), Scopus, and Web of Science. The research question was as follows: which molecules present in saliva have utility to be used as biomarkers for the early detection of oral cancer? Sixty-two studies were included. Over 100 molecules were assessed. Most of the markers were oriented towards the early diagnosis of OSCC and were classified based on their ability for detecting OSCC and oral potentially malignant disorders (OPMDs), OSCC outcome prediction, and the prediction of the malignant transformation of OPMDs. TNF-α, IL-1β, IL-6 IL-8, LDH, and MMP-9 were the most studied, with almost all studies reporting high sensitivity and specificity values. TNF-α, IL-1β, IL-6 IL-8, LDH, and MMP-9 are the most promising salivary biomarkers. However, more studies with larger cohorts are needed before translating the use of these biomarkers to clinical settings.

MiR-32-5p promoted epithelial-to-mesenchymal transition of oral squamous cell carcinoma cells via regulating the KLF2/CXCR4 pathway

Oral squamous cell carcinoma (OSCC) is one of the most common carcinomas of the oral cavity. However, the regulatory mechanisms on miR-32-5p remain poorly understood in OSCC. The expression of miR-32-5p, Krüppel-like factor 2 (KLF2), C-X-C motif chemokine receptor 4 (CXCR4), and epithelial-to-mesenchymal transition (EMT)-related proteins (E-cadherin, Vimentin, N-cadherin, and Snail) were evaluated were assessed using RT-qPCR and Western blot. 3-(4, 5-Dimethylthiazolyl2)-2, 5-diphenyltetrazolium bromide assay, wound healing assay, and transwell assay were employed to detect cell proliferation, migration, and invasion of OSCC cells. Finally, dual-luciferase reporter assay was performed to verify the binding relationship between KLF2 and miR-32-5p. MiR-32-5p was highly expressed while KLF2 was lowly expressed in OSCC cells, and miR-32-5p knockdown or KLF2 overexpression could markedly reduce cell proliferation, migration, invasion, and EMT of OSCC cells. What is more, KLF2 was the target of miR-32-5p, and knockdown of KLF2 abolished the inhibitory effect of miR-32-5p inhibitor on progression of OSCC. Finally, CXCR4 expression was negatively regulated by KLF2, and inhibition of CXCR4 obviously alleviated the biological effects of si-KLF2 on the progression of OSCC. MiR-32-5p could enhance cell proliferation, migration, invasion, and EMT of OSCC cells, and the discovery of miR-32-5p/KLF2/CXCR4 axis might provide potential therapeutic targets for OSCC.