MicroRNAs as potential diagnostic and prognostic biomarkers in melanoma

Melanoma is a life-threatening malignancy with poor prognosis and a relatively high burden of mortality in advanced stages. The efficacy of current available therapeutic strategies is limited, with a survival rate of less than 10%. Despite rapid advances in biomarker-guided drug development in different tumour types, including melanoma, only a very small number of biomarkers have been identified. Recently, microRNAs (miRNAs) have emerged as a molecular regulator in the development and progression of melanoma. Aberrant activation of some known miRNAs, e.g. let-7a and b, miR-148, miR-155, miR-182, miR-200c, miR-211, miR-214, miR-221 and 222, has been recognised to be linked with melanoma-associated genes such as NRAS, microphthalmia-associated transcription factor, receptor tyrosine kinase c-KIT, AP-2 transcription factor, etc. There is accumulating evidence suggesting the potential impact of circulating miRNAs as diagnostic and therapeutic markers in diseases. In addition, miRNAs have turned out to play important roles in drug-resistance mechanisms; suggesting their modulation as a potential approach to overcome chemoresistance. This review highlights recent preclinical and clinical studies on circulating miRNAs and their potential role as diagnosis, and therapeutic targets in melanoma.