Overexpression Correlates with Metastatic Phenotype in BRAF Positive Papillary Thyroid Carcinoma.

The ability of cancer to metastasize is regulated by various signaling pathways, including transforming growth factor β (TGFβ), also implicated in the upregulation of Snail-1 transcription factor in malignant neoplasms. B-type Raf kinase gene (BRAF), the most common driving mutation in papillary thyroid carcinoma (PTC), induces epithelial to mesenchymal transition (EMT) in thyroid cancer cells through changes in the Snail-1 level, increasing cell migration and invasion. However, little is known about the mechanism of Snail-1 and BRAF relations in humans. Our study included 61 PTC patients with evaluated BRAF mutation status. A total of 18 of those patients had lymph node metastases-of whom 10 were BRAF positive, and 8 negative. Our findings indicate that the expression of Snail-1, but not TGFβ1, correlates with the metastatic phenotype in PTC. This is the first piece of evidence that the upregulation of Snail-1 corresponds with the presence of BRAF mutation and increased expression of Snail-1 in metastatic PTC samples is dependent on BRAF mutation status.