Non-Coding RNAs in Oral Cancer: Emerging Roles and Clinical Applications

SIMPLE SUMMARY: Oral cancer (OC) is one of the most prevalent cancers in the world. Despite improvements in therapies, OC still has a poor survival rate of about 50%, with metastasis being the worst-case scenario. Thus, there is an urgent need to understand the disease process and to develop diagnostic and therapeutic strategies for OC. Advancement of high throughput genome sequencing shows that more than 90% of the human genome encodes non-coding transcripts that do not code for any protein. In this review, we discuss the role of various types of these non-coding RNAs (ncRNAs) in OC and their promising clinical implications. Dysregulated expressions of ncRNAs are associated with OC initiation and progression, as well as therapy resistance. Differential expressions of these ncRNAs in blood or saliva have indicated their potential diagnostic and prognostic importance. In this review, we have summarized all the promising aspects of ncRNAs in the management of OC. ABSTRACT: Oral cancer (OC) is among the most prevalent cancers in the world. Certain geographical areas are disproportionately affected by OC cases due to the regional differences in dietary habits, tobacco and alcohol consumption. However, conventional therapeutic methods do not yield satisfying treatment outcomes. Thus, there is an urgent need to understand the disease process and to develop diagnostic and therapeutic strategies for OC. In this review, we discuss the role of various types of ncRNAs in OC, and their promising clinical implications as prognostic or diagnostic markers and therapeutic targets. MicroRNA (miRNA), long ncRNA (lncRNA), circular RNA (circRNA), PIWI-interacting RNA (piRNA), and small nucleolar RNA (snoRNA) are the major ncRNA types whose involvement in OC are emerging. Dysregulated expression of ncRNAs, particularly miRNAs, lncRNAs, and circRNAs, are linked with the initiation, progression, as well as therapy resistance of OC via modulation in a series of cellular pathways through epigenetic, transcriptional, post-transcriptional, and translational modifications. Differential expressions of miRNAs and lncRNAs in blood, saliva or extracellular vesicles have indicated potential diagnostic and prognostic importance. In this review, we have summarized all the promising aspects of ncRNAs in the management of OC.