Rapid multiplex real-time PCR by molecular beacons for different BRAF allele detection in papillary thyroid carcinoma.

BRAF is an oncogene that is commonly mutated in both melanomas and papillary thyroid carcinomas (PTCs). Usually, mutations in the codons 600 or 601 lead to constitutive activity in the Ras-mitogen-activated protein kinase pathway and, recently, the BRAF deletion was described as a relevant risk factor for loco-regional PTC lymph node metastasis. For these reasons, BRAF mutations may be considered a key genetic factor for the metastatic progression of PTC and also for other tumors such as melanoma and colon cancer and a new BRAF-specific therapeutic strategy was already suggested. In this report we describe the development of a rapid qualitative fluorescent real-time polymerase chain reaction assay designed for the detection of BRAF deletion using 2 specific molecular beacons. The assay is able to detect in a single tube the homozygous as well the heterozygous genotypes. The procedure combines the great sensitivity of the polymerase chain reaction, the specificity provided by allele-specific molecular beacons, and the throughput of a multicolor fluorescence detection procedure. This technique, together with an earlier described real-time test specific for V600E and K601E will be useful for research and molecular diagnostic laboratories involved in the study of BRAF-related neoplasia.