Scientists at Johns Hopkins have found that a mutation in the gene that triggers production of a tumor growth protein is linked to poorer outcomes for patients with papillary thyroid cancer (PTC). A report on the study is published in the December issue of The Journal of Clinical Endocrinology and Metabolism.
Mingzhao Xing, M.D., Ph.D., an assistant professor in the Division of Endocrinology and Metabolism at The Johns Hopkins University School of Medicine, led the multi-center study. "This discovery should help physicians rate risk levels for patients with PTC," he says.
The gene, called BRAF, is part of a signaling pathway that, when activated, is known to cause tumor growth, and mutations in BRAF have been linked to a variety of human cancers, the researchers say.
For the study, Xing and colleagues looked at information from 219 PTC patients from 1990 to 2004. The relationship among BRAF mutations, initial tumor characteristics, cancer recurrence and clinical outcomes was analyzed.
Results showed a "significant association" between BRAF mutation and spread of the cancer from the thyroid, lymph node metastasis, and advanced tumor stage at the time of surgery to remove the cancerous thyroid gland. The thyroid, a gland located beneath the voice box (larynx) that produces thyroid hormone, helps regulate body cell growth and metabolism. Results also showed that, given an average follow-up of three to four years, 25 percent of patients with BRAF mutations experienced tumor recurrence compared to 9 percent without evidence of BRAF mutations.
BRAF mutation was also an independent predictor of recurrence in patients with early disease, with 22 percent recurrence in those who had BRAF mutations versus only 5 percent in patients without the mutation.
Finally, BRAF mutation was more frequently associated with treatment failure in recurrent disease, according to the study.