BRAF Rearrangement

This test uses a break-apart BRAF probe to detect the BRAF-KIAA1549 fusion common in low-grade astrocytomas and to detect any other known and potential BRAF rearrangement partners. The BRAF-KIAA1549 fusion causes constitutive BRAF kinase activation and is found in about 70% of pilocytic astrocytomas and 15% of other low-grade gliomas. Frequency diminishes with patient age, from 80% in the first decade to <10% in pilocytic astrocytomas in patients over 40. The detection of a BRAF fusion is most suggestive of a low-grade glioma. Prognosis associated with BRAF fusions shows a positive trend. BRAF translocations have been reported in thyroid cancer and melanoma but are infrequent. MEK inhibitors, alone and in combination with BRAF inhibitors, are being investigated. BRAF inhibition alone may lead to activation of a feed-back loop with up-regulation and potential for further tumor growth. BRAF Mutation Analysis is also available for detection of the V600E mutation (and others) found in non-pilocytic gliomas, thyroid cancer, and melanoma.