BRAF mutations are linked to more advanced and aggressive cancer

This study examined whether there is a link between having an abnormal BRAF gene and clinical outcomes of colorectal cancer.

Colorectal cancer is the third most common cancer in the world. There is no one cause of colorectal cancer but several environmental and genetic factors are known to contribute to its development. One gene that is known to play an important role in colorectal cancer is BRAF (B-type Raf proto-oncogene). Patients with a mutated (abnormal) BRAF gene respond less effectively to some treatments. However, it is unclear whether having a mutated BRAF gene can also predict poorer disease outcome.

The authors analyzed 25 research articles related to the outcomes of patients with BRAF mutations. Together these articles included 11,55 patients with colorectal cancer. Overall 10.8% of the patients had a BRAF mutation. Patients’ tumors were also analyzed under the microscope to check how closely the cancer cells look like normal cells. The more abnormal the cells look (poorly differentiated) the more aggressive the tumor is considered to be.

The risk of having a mutated BRAF gene was higher for female patients and patients over 60 years. Patients with the BRAF mutation had 4.85 times higher odds of having the tumor located in the upper colon than in the lower colon or rectum.

Having mutated BRAF was also associated with having a more advanced cancer. The odds of having a stage III or IV cancer was 59% higher in patients with a mutated BRAF gene. The odds of having a more aggressive tumor was 3.89 times higher in patients with a mutated BRAF gene. The odds of having more mucin (gel-like substance that coats the bowel) producing cells in the tumor was 3 times higher in patients with a mutated BRAF gene.

The authors concluded that the BRAF mutation is linked to more advanced and aggressive cancer. They suggest that screening patients for BRAF mutations could be useful for helping predict patient outcomes.