MicroRNA Expression Profiles Associated with Mutational Status and Survival in Malignant Melanoma

In order to improve our understanding of microRNA (miRNA) deregulation in melanoma development and possible consequences for patient survival, miRNA expression profiles were determined, using an array based approach, in melanoma tumors, melanoma cell lines and normal melanocytes. Differentially expressed miRNAs were evaluated in relation to clinical characteristics, patient prognosis in terms of melanoma-specific survival, and mutational status for BRAF and NRAS. Agilent microarray platform containing 470 miRNAs was used to determine miRNA expression profiles in 3 normal melanocytes (as non-neoplastic control), 21 melanoma cell lines and 16 clinical samples from fresh frozen regional lymph node metastases. To validate the microarray platform, the expression levels of some miRNAs were evaluated using RT-PCR and the correlation between the two platforms was assessed using Pearson Correlation analysis. The results obtained were further verified and confirmed by RT-PCR in an independent set of melanoma samples. Association between deregulated miRNAs and survival was determined by Univariate Cox proportional hazards model and log rank test.