Browsing by Author "Nunes, Maria Inês Marçal"
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- Molecular characterization of cutaneous melanomaPublication . Nunes, Maria Inês Marçal; Pópulo, Helena Isabel; Ferreira, Ana Paula Soares; Ladeira, CarinaABSTRACT - Cutaneous melanoma (CM) is the least frequent but deadliest kind of skin cancer, harboring one of the highest mutation rates among all malignancies. The most frequently altered genes are BRAF, NRAS, and TERT promoter. CM treatments have failed to provide good response rates and treatment resistance development is rather frequent. As a result, additional approaches to research, such as microRNA expression analysis, including miR-125a, miR-155, and miR-579, have been investigated as potential biomarkers. Therefore, we aimed to identify potential CM biomarkers by searching for a relation between the presence of CM molecular alterations with the patients' clinicopathological data. For that, DNA and RNA were extracted from FFPE tissues of primary tumors, metastases, relapses, and sentinel lymph nodes. PCR, qPCR, and Sanger sequencing techniques were performed to evaluate molecular alterations, such as the presence of mutations in the BRAF and NRAS genes and TERT promoter and evaluation of miR-125a, miR-155, and miR-579 expression levels. The obtained data demonstrated that the most frequently mutated gene was BRAF (47%), followed by TERTp (37%) and NRAS (20%), with the latter associated with a better prognosis. Regarding multiple gene mutations, TERTp and BRAF mutations often co-occur, in opposition to BRAF and NRAS mutations. No significant associations were found between miR-125a and clinicopathological or follow-up data. However, increased miR-155 was linked to better overall survival, while elevated miR-579 was associated with favorable prognostic traits, and improved progression-free survival. To conclude, NRAS mutations are associated with better CM prognosis, and miR-579 shows potential for prognosis assessment in melanoma patients.