BRAF V600E mutation and correlation with clinicopathologic features in radioactive iodine refractory papillary thyroid carcinoma

Abstract

Objective: To define the rate of BRAF V600E mutation in radioactive iodine (RAI) refractory papillary thyroid carcinoma (PTC). The correlation BRAF V600E mutation with some clinicopathologic features in RAI refractory PTC. Subject and method: 92 patients with RAI refractory PTC were operated recurrent lesions at 108 Military Central Hospital from 9/2009 to 3/2018. Recurrent lesions were evaluated histopathological characteristics, immunohistochemical staining with BRAF V600E (Ventana, Roche), BRAF V600E gene test by real-time PCR. Evaluating the status of mutated BRAF V600E and correlate with some clinicopathologic features. Result: Average age: 47.1 ± 15.6 (12 - 81); the rate of BRAF V600E mutation accounted for 80.4%; the average age of unmutated BRAF V600E RAI refractory PTC group (40.2 ± 17.2) was lower than the group of BRAF V600E mutation (48.5 ± 14.9) (p=0.042); BRAF V600E mutation in early-stage disease (I - II) had a higher rate than ones in advanced disease (II-IV); similarly, this gene mutation occurred more frequent in the group received more than 600mCi cumulative dose of RAI compared with the group received less than 600mCi cumulative dose. There was no correlation of BRAF V600E mutation with age, tumor size, lymph node, distant metastasis. BRAF V600E mutation in tall cell variant of PTC was seen more frequently than other variants and it was also seen in cases of extracapsular lymph node invasion. There was no relationship between the existence of mutated BRAF V600E with vessel invasion and calcification. Conclusion: The rate of BRAF V600E mutation in RAI refractory PTC is high, accounting for 80.4%. It correlates with some clinicopathologic characteristics such as disease stage, cumulative dose of radioactive iodine, tall cell variant of PTC; no correlation of BRAF V600E mutation with age, tumor size, lymph node and distant metastasis, extracapsular lymph node invasion