Macrocephaly points to likelihood of PTEN mutation in follicular thyroid cancer patients

Among people with a mutation of a particular gene called PTEN, the rate of differentiated thyroid cancer (DTC) is between 3 and 10 percent, but until recently, researchers had not tabulated how many patients with follicular thyroid cancer (FTC) typically display the mutation.

However, scientists from the Cleveland Clinic and the Ohio State University Medical Center have addressed this issue and come up with a figure. After sequencing the genes and analyzing the follicular tissue of 42 Americans with FTC, the team determined that 4.8 percent carried a PTEN mutation.

In particular, the research group noticed a strong correlation between FTC, macrocephaly and PTEN variations.

The PTEN gene controls the creation of phosphatase and tensin homolog in the body. According to the National Institutes of Health, this protein is present in almost all cells. It suppresses tumors by controlling the rate of cell growth and division.

However, mutations of the PTEN gene can restrict or disable the production of this protein, dramatically increasing the risk of a number of carcinomas, including thyroid cancer.

In the new study, which appeared in the journal Thyroid, scientists reported making a discovery while testing patients for Cowden syndrome, a rare inherited condition that makes the skin and organs prone to small benign growths. While measuring head circumferences, researchers found that 10 DTC patients had macrocephaly, meaning that their heads were unusually large, with a circumference exceeding the 97th percentile.

Macrocephaly, which is a major criterion in the diagnosis of Crowden syndrome, ended up being a strong predictor of the likelihood of PTEN variations.

In fact, the team found that the two patients with the most dramatic PTEN mutations both suffered from FTC, macrocephaly and either intestinal polyps or a goiter.

Researchers concluded that when testing patients for a genetic predisposition to DTC - and especially to FTC - physicians should measure head circumference as part of the clinical exam.

FTC is the second-most common type of thyroid carcinoma, accounting for 25 percent of thyroid cancer diagnoses in the U.S., according to the Columbia University Department of Surgery.