V-raf murine sarcoma viral oncogene homolog B1 V600E mutations in different subtypes of papillary thyroid carcinoma and the association with pathological features

Abstract

Objective To investigate the V600E mutations of V-raf murine sarcoma viral oncogene homolog B1 (BRAF) gene in different subtypes of papillary thyroid carcinoma (PTC). Methods We analyzed retrospectively a series of 411 patients, treated for PTC from 2014 to 2016. The BRAF V600E mutation was detected by real-time quantitative polymerase chain reaction (Real-time PCR). Results Among 411 cases, BRAF V600E mutation was found in 88.4% (321/363) of classical PTCs, in 41.7% (5/12) of follicular variant, in 100.0% (23/23) of tall cell PTCs, and in 80.0% (4/5) of oncocytic variant. Chi square analysis showed that there were significant differences in BRAF mutation between the follicular variant and classical PTCs (χ2=18.435, P=0.001), and in the tumor size and capsule invasion between the classical and tall cell PTCs (χ2=13.563, P=0.000; χ2=4.115, P=0.043). Univariat binary Logistic regression analysis revealed that there was no significant correlation between BRAF V600E mutation and age, sex, tumor size, lymph node metastasis and capsule invasion in classical and follicular variant PTCs (P values were 0.529, 0.682, 0.271, 0.623, 0.550 and 0.921, 1.000, 0.560, 0.560, 0.999 respectively). Conclusion The mutation rate of BRAF gene in high-risk subtypes was higher than that of low-risk subtypes of PTC in general, while the tall cell subtype has larger size and further capsule invasion than classical PTCs. There was no significant correlation between BRAF mutation and age, sex, tumor size, lymph node metastasis and capsule invasion in classical, follicular variant PTCs and tall cell PTCs. Key words: Papillary thyroid carcinoma; Pathological subtype; V-raf murine sarcoma viral oncogene homolog B1 V600E