New insights in melanoma biomarkers: long-noncoding RNAs

Abstract

Melanoma is one of the leading cancers worldwide, distinguished for its malignancy and low survival rates. Although the poor outcome could improve with an early diagnosis and a good monitoring of the disease, current melanoma biomarkers display several limitations which make them useless. Interestingly, long-noncoding RNAs are secreted into the bloodstream inside exosomes by a wide range of malignant cells, and several of them have been validated as promising circulating molecular signatures of other tumors, but not melanoma. In this review we propose to explore the booming field of long-noncoding RNAs in order to find potential candidates to be tested as novel melanoma biomarkers, with the ultimate goal of improving melanoma detection, diagnosis and prognosis.

Keywords: biomarkers; cancer; lncRNAs; melanoma.

Figure 1.. Schematic protocol for analyzing the presence of circulating melanoma long-noncoding RNAs in the blood sample of a patient.

The protocol starts with collecting a sample of peripheral venous blood from the patient (regular procedure for venepuncture) into EDTA-K2 tubes to avoid coagulation, and its storage at 4°C until the subsequent processing. To obtain plasma, the whole blood is centrifuged at 160 g at RT to get rid of erythrocytes and blood cells. Plasma is stored at -80°C until exosome extraction. Plasma exosome vesicles can be precipitated either by ultracentrifugation, a precipitation reagent or a commercial kit. Exosomes are then lysed and the RNA is purified, either by using TRIzol or a commercial kit. Finally, the analysis is performed by synthesizing the cDNA and quantifying the levels of the lncRNAs of interest by qRT-PCR with specific primers. lncRNA: Long-noncoding RNA; RT: Room temperature.