What it is: The BRAF gene encodes the B-Raf protein which is involved with several tyrosine kinase receptors. Its activation results in cell growth and cell proliferation.
The most common genetic mutation of the kinase involves V600E.

Why the test is done:
Melanoma: Detection of the BRAF V600E mutation predicts the sensitivity of the neoplasm to BRAF and MEK inhibitors.
ΜΜΚΠ: Detection of the BRAF V600E mutation predicts the sensitivity of the neoplasm to BRAF and MEK inhibitors.
Colorectal cancer: Detection of BRAF V600E mutation predicts sensitivity to the combination of BRAF inhibitor with EGFR inhibitor.
Thyroid cancer:
1. The presence of BRAF V600E mutation in papillary thyroid carcinoma is associated with a more aggressive course of the carcinoma.
2. In anaplastic thyroid carcinoma the presence of BRAF V600E mutation predicts sensitivity to response to BRAF (dabrafenib) and MEK (trametinib) inhibitors.
3. The presence of a mutation in BRAF V600E cofactors in favor of papillary thyroid cancer over other subtypes.
Frequency:
Melanoma: Approximately 50% of melanomas have a BRAF mutation, most commonly due to exposure to solar radiation.
ΜΜΚΠ: Less than 5% of cases. Probably more common in non-smokers and in adenocarcinomas with a microfollicular growth pattern.
Colorectal cancer: Occurs in about 10% of cases. It shares similar clinicopathological features with colorectal tumours with deficiency of mismatch base repair (dMMR) mechanisms.
Thyroid cancer: Found in approximately 50% of papillary thyroid carcinomas, 20% of anaplastic thyroid carcinomas, and in the more aggressive histological subtypes (e.g., tall cell).