Rastreio da presença da mutação BRAFV600E em carcinoma papilífero de tireoide associado à tireoidite de Hashimoto

Abstract

Background: The BRAFV600E mutation is the most prevalent mutation in patients diagnosed with papillary thyroid cancer (PTC). The clinical meaning of Hashimoto's thyroiditis (HT) associated with PTC has been studied, and so its association with BRAFV600E mutation. Objective: Evaluate the prevalence of BRAFV600E mutation in PTC associated with HT and its association with clinical and pathological features. Methods: Retrospective study of unicentric transversal section with consecutive PTC on patients treated at Hospital São Rafael - Monte Tabor, Salvador, Bahia. Clinical and pathological data were gathered through analysis of electronic and physical records. Polymerase chain reaction was done in order to amplify the exon 15 of BRAF gene through DNA extracted from paraffin-embedded tumor tissue post thyroidectomy. PCR readings were done and the presence of BRAFV600E mutation was confirmed through direct sequencing. Results: 43 patients diagnosed with PTC were studied. Among those, 17 (39,4%), were simultaneously diagnosed with HT. within the latter, 7 were confirmed carriers of the BRAFV600E mutation through genetic study, and 10 (66,7%) were BRAFV600E negative. The presence of these two conditions and the BRAFV600E mutation were confronted. Chi square test provided a significant negative association (p:0,008). In a multivariate logistic regression analysis, this relation was independent (p:0,024). Conclusions: The coexisting presence of HT and PTC may be an independent protective factor to the BRAFV600E mutation.