As there are no approved molecular biomarkers routinely available in clinical practices as promising prognosticators in NPC and HNC, this study aims to ameliorate this deficit. While the aforementioned narrative reviews and systematic reviews and meta-analyses indicate possible diagnostic, prognostic and therapeutic use of miRNAs in other subtypes of HNC, quantitative and qualitative evaluation of miRNAs on patient survival in NPC through a systematic review and meta-analysis has not yet been conducted. However, the authors only explored the possible pathways of NPC pathogenesis and signalling pathways and did not discuss the relationship between the miRNAs expression and patients survival. A previous meta-analysis has performed miRNA target prediction and pathway enrichment analysis to identify the functional genes involved in the meta-signature regulation of NPC. Findings from previous studies have also shown that the down-regulation of miRNAs can be associated with enhanced survival of NPC patients. Although circulating EBV PCR in blood before and after treatment showed some prognostic capability, the results remain inconsistent.ДЄ few reviews have also highlighted the deregulated expression of miRNAs and their association with the progression of NPC and subsequently, its prognosis. This knowledge could potentially be valuable for head and neck health care. Although previous studies have conducted analysis regarding the relevant anatomical sub-site of HNC, there is still a knowledge gap regarding the prognostic impact of miRNAs in NPC. Many studies have investigated and reported the prognostic significance of miRNAs in multiple types of HNC, including oropharyngeal carcinoma and laryngeal squamous cell carcinoma through narrative reviews and systematic reviews and meta-analyses. Furthermore, EBV encoded miRNA has been shown to play a complementary role to the viral proteins which are expressed in malignant cells of the NPC, which promote survival and proliferation of NPC cells, leading to the evasion of host immune responses. Identification of miRNAs may function as therapeutic targets and provide new avenues to treat NPC. MicroRNAs play an essential role in cancer either as tumour suppressors/repressors or promoters in many malignancies including NPC, therefore giving miRNAs potential prognostic utility. MicroRNAs (miRNAs) are small non-coding RNAs, which may also act as oncogenes by influencing multiple cancer mechanisms, including metastasis. However, despite these developments in the treatment strategies for NPC in recent years, it is still considered as an aggressive disease due to its invasive nature, delayed diagnosis, relatively poor prognosis and overall patient survival. Advances in radiotherapy and comprehensive chemotherapy strategies have significantly improved clinical outcome of the patients with primary NPC. The molecular landscape of NPC is defined by an array of genetic and epigenetic variations, which, in most NPC cases express a malignant phenotype, when combined with dormant Epstein-Barr Virus (EBV) infection. Nasopharyngeal carcinoma (NPC) is a malignant epithelial Head and Neck Carcinoma (HNC) and is primarily prevalent in the Asian population, with 40% of the 84,000 new cases globally, being reported in China, Malaysia, Singapore, Indonesia, Vietnam and Brunei. ДЇunding: The authors received no specific funding for this work.Д¬ompeting interests: The authors have declared that no competing interests exist.

This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Дata Availability: All relevant data are available from the Figshare repository through the following links. Received: JAccepted: DecemPublished: February 8, 2019Д¬opyright: В© 2019 Sabarimurugan et al. PLoS ONE 14(2):Д®ditor: Yukinori Takenaka, Osaka General Medical Center, JAPAN Citation: Sabarimurugan S, Kumarasamy C, Baxi S, Devi A, Jayaraj R (2019) Systematic review and meta-analysis of prognostic microRNA biomarkers for survival outcome in nasopharyngeal carcinoma.

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