BRAFV600E is associated with increased uPA levels in papillary thyroid cancer

Objectives: Papillary thyroid carcinomas (PTC) with the BRAFV600E mutation have been associated with greater local invasion and regional metastasis. The aim of this study is to determine the extent to which BRAFV600E mutation status predicts upregulation of the urokinase plasminogen activator (uPA), an important mediator of invasion and metastasis, in patient samples of PTC. Study Design: Prospective study using 13 patient thyroid tissue samples obtained over 6 years at the New York Eye & Ear Infirmary. Methods: DNA and RNA were obtained from patient PTC and matched normal thyroid tissue samples using the Trizol method. BRAFV600E genotyping was performed using the TaqMan SNP assay, and RNA was analyzed for differences in uPA transcription levels (relative to matched normal thyroid tissue) by qRT-PCR. Results: 54% of the PTC samples possessed the BRAFV600E mutation. PTC samples with the BRAFV600E mutation displayed significantly higher uPA transcription levels than those samples with wild-type BRAF (5.883 vs. 1.27-fold higher RNA levels than corresponding normal thyroid tissue, p<0.05, Wilcoxon signed-rank test). Additionally, uPA RNA levels were significantly higher in patients with nodal metastasis (p<0.05). Conclusions: These data provide new evidence of the roles of BRAF ^V600E and uPA in PTC invasive pathology, and demonstrate for the first time that BRAFV600E status is able to predict higher uPA levels in PTC.