The frequency and clinical implications of the BRAF^v600E mutation in papillary thyroid cancer patients in Korea over the past two decades

Background: Over the past several decades, there has been a rapid worldwide increase in the prevalence of papillary thyroid cancer (PTC) as well as a number of changes in the clinicopathological characteristics of this disease. BRAF^V600E, which is a mutation of the proto-oncogene BRAF, has become the most frequent genetic mutation associated with PTC, particularly in Korea. Thus, the present study investigated whether the prevalence of the BRAF^V600E mutation has increased over the past two decades in the Korean population and whether various PTC-related clinicopathological characteristics have changed. Methods: The present study included 2,624 patients who underwent a thyroidectomy for PTC during two preselected periods; 1995 to 2003 and 2009 to 2012. The BRAF^V600E mutation status of each patient was confirmed using the polymerase chain reaction-restriction fragment length polymorphism method or by the direct sequencing of DNA. Results: The prevalence of the BRAF^V600E] mutation in Korean PTC patients increased from 62.2% to 73.7% (P=0.001) over the last two decades. Additionally, there was a greater degree of extrathyroidal extension (ETE) and lymph node metastasis in 2009 to 2012 patients with the BRAF^V600E mutation and a higher frequency of thyroiditis and follicular variant-PTC in 2009 to 2012 patients with wild-type BRAF. However, only the frequency of ETE was significantly higher in 1995 to 2003 patients with the BRAF^V600E mutation (P=0.047). Long-term recurrence rates during a 10-year median follow-up did not differ based on BRAF^V600E mutation status. Conclusion: The BRAF^V600E mutation rate in Korean PTC patients has been persistently high (approximately 70%) over the past two decades and continues to increase. The present findings demonstrate that BRAF^V600E-positive PTC was associated with more aggressive clinicopathological features, especially in patients who were recently diagnosed, suggesting that BRAF^V600E mutation status may be a useful prognostic factor for PTC in patients recently diagnosed with this disease.