European Journal of Molecular & Clinical Medicine

Abstract

Despite technological advancements, the mortality rates of oral squamous cell carcinomas (OSCCs) are continuously rising mainly due to late diagnosis.  OSCC is preventable if detected early.  The majority of oral cancercases are preceded by a transition fromclinically evident oral potentially malignant disorders ( OPMDs)  However,  prediction ofthe possible malignant transformation risk in OPMDs is difficultsince there are no clinicallyreliable non-invasive biomarkers yet.  The genesis, progression, and tumour microenvironment of oral cancer appear to be significantly influenced by microRNAs, a type of small noncoding RNAs involved in gene regulation. These characteristics, along with the fact that microRNAs are stable over a range of tissues and liquid biopsies and exhibit differential expression in cancer cells, put microRNAs at the top of the list of prospective biomarkers with diagnostic and prognostic significance. For the last few years, aberrant expression of several miRNAshad been reported as a common occurrence in OPMDs and OSCC.  Those studies on tumour specimens, serum/plasma or saliva from OSCC  patients had identified specific miRNA signatures that could be clinically useful in the diagnosis, prognosis and s therapeutic targets. This review highlights the roles played by important microRNAs in the emergence, development, and maintenance of the oral cancer microenvironment. The possibility of these small RNA species as non-invasive reliable indicators of malignant transformation risk of  OPMDs and for the early detection of oral lesions is also discussed. Finally, we discuss the potentials and constraints of microRNAs as novel diagnostic and therapeutic approaches.