Papillary thyroid carcinoma (PTC) accounts for approximately 80% of all thyroid cancers. The
BRAF
gene mutation (V600E) is the most common genetic alteration in PTC (detected in up to 83% of cases; Frasca
et al
., 2008). The detection of the
BRAF
proto-oncogene mutation (V600E) can help in the diagnosis of thyroid tumors, especially for indeterminate cases, and may also predict a favourable response to inhibitors targeting
RAF
and other MEK pathway members.
A
ctivating mutations of the
BRAF
oncogene
have been observed in approximately 50% of malignant melanomas (Rodolfo
et al
., 2004). The V600E mutant accounts for 80-90 percent of these mutations, with the next most common V600K mutation representing 6-16% (Rubinstein
et al
., 2011).
The presence of the V600E or the V600K mutation may indicate if a tumour is likely to respond to therapy targeting the
BRAF
pathway.
Mutations in the
BRAF
gene are found in up to 15% of colorectal cancer patients, the presence which is associated with decreased overall survival. Several studies have reported that patients with metastatic CRC that harbor
BRAF
mutations do not respond to anti-
EGFR
antibody agents such as Cetuximab or Panitumumab. Similarly, response to
BRAF
inhibitors including Vemurafenib and Dabrafenib may also be low; response to other therapies is unknown at this time.
BRAF
mutations are usually found in tumours wild type for
EGFR, RAS
,
ALK
rearrangements etc.