Salivary Micro RNA as a Biomarker to Predict the Malignant Transformation of Oral Potentially Malignant Disorders: A Systematic Review

Background: Oral potentially malignant disorders (OPMDs) are oral mucosal disorders which have a high potential to turn into malignancy. A recent report suggests that 16%-62% of epithelial dysplasia cases of OPMDs undergo malignant transformation, showing the need for early detection of malignancy in these disorders. Micro RNA (miRNA) plays an important role in cellular growth, differentiation, apoptosis, and immune response, and hence, deregulation of miRNA is considered a signature of oral carcinogenesis. Materials and Methods: A search was done using MeSH terms in the PubMed/Medline, Scopus, EBSCO and Springerlink and finally, twelve studies were included in this systematic review. A quality assessment based on the Quality Assessment of Diagnostic Accuracy Studies 2 tool was used to obtain a graph of risk of bias using Revman 5.4.1 software. Results: The results of the study revealed that miR-21, miR-31, and miR-184 were overexpressed in OPMDs, whereas miR- 145 was under-expressed in OPMDs. It was demonstrated that study by Maheshwari et al. had the lowest risk of bias. Conclusion: This systematic review explored the potential of expression of salivary miRNA in OPMDs. This could pave the way to utilize saliva as a surrogate marker in diagnosing early malignant changes in OPMDs.