Interplay between small and long non-coding RNAs in cutaneous melanoma: a complex jigsaw puzzle with missing pieces.

The incidence of cutaneous melanoma (CM) has increased in the past few decades. The biology of melanoma is characterized by a complex interaction between genetic, environmental and phenotypic factors. A greater understanding of the molecular mechanisms that promote melanoma cell growth and dissemination is crucial to improve diagnosis, prognostication, and treatment of CM. Both small and long non-coding RNAs (ncRNAs) have been identified to play a role in melanoma biology; microRNA and long ncRNA expression is altered in transformed melanocytes and this in turn has functional effects on cell proliferation, apoptosis, invasion, metastasis, and immune response. Moreover, specific dysregulated ncRNAs were shown to have a diagnostic or prognostic role in melanoma, and to drive the establishment of drug resistance. Here, we review the current literature on small and long non-coding RNAs with a role in melanoma, with the aim of putting some order in this complex jigsaw puzzle.