Detection of plasma BRAF(V600E) mutation is associated with lung metastasis in papillary thyroid carcinomas

PURPOSE

The BRAF(V600E) mutation represents a novel indicator of the progression and aggressiveness of papillary thyroid carcinoma (PTC). The purpose of this study was to determine the clinical significance of free circulating mutant BRAF(V600E) in predicting the advanced disease of PTC.

MATERIALS AND METHODS

Seventy seven matched tumor and plasma samples obtained from patients with both benign and PTC were analyzed for BRAF(V600E) mutation using a peptide nucleic acid (PNA) clamp real-time polymerase chain reaction (PCR).

RESULTS

The BRAF(V600E) mutation was absent in tumor DNA samples obtained from patients with benign follicular adenomas or adenomatous goiter. In contrast, 49 of 72 (68.1%) PTC tumors were positive for the BRAF(V600E) mutation. Among them, 3 (6.1%) patients with PTC were positive for BRAF(V600E) mutation in plasma and tumor. However, all 3 patients (100%) had lateral lymph node and lung metastasis.

CONCLUSION

These findings suggest that the BRAF(V600E) mutation can be detected using a PNA clamp real-time PCR in the blood of PTC patients with lung metastasis. Future studies are warranted to determine clinical significance of serum BRAF(V600E) mutation in large prospective studies.

BRAFV600E mutation does not serve as a prognostic factor in Korean patients with papillary thyroid carcinoma

OBJECTIVES

In recent years, BRAF(V600E) mutation has emerged as a promising prognostic marker for risk stratification of patients with papillary thyroid carcinoma (PTC). However, routine use of this marker has been questioned. In some parts of the world, particularly in Korea, the incidence of BRAF(V600E) mutation is too high to have true prognostic value. The relatively low number of tumors without BRAF(V600E) mutation would prejudice the efficient use of this marker in the Korean population.

METHODS

The study involved 107 patients with histologically confirmed conventional PTC after surgical management for thyroid cancer from April 2010 to December 2010. BRAF(V600E) mutation analysis was performed by polymerase chain reaction (PCR)-based amplification of DNA extracted from paraffin-embedded tumor specimens, and the relationship between BRAF(V600E) mutation and various prognostic factors was investigated.

RESULTS

BRAF(V600E) mutation was found to be present in 85 (79.4%) of 107 patients with conventional PTC. Analysis of the clinical characteristics as function of the presence or absence of BRAF(V600E) mutation revealed no differences between the BRAF(V600E)-positive and BRAF(V600E)-negative patients. Moreover, BRAF(V600E) mutation was not correlated with any of the prognostic factors including age ≥45 years, male gender, tumor size ≥1cm, multifocality, extra-thyroidal extension, concurrent Hashimoto's thyroiditis, and lymph node metastasis neither in the univariate nor in the multivariate analysis.

CONCLUSIONS

BRAF(V600E) mutation does not significantly reflect tumor aggressiveness in Korean patients with conventional PTC. We consider that BRAF(V600E) mutation does not possess prognostic value in Korea, where it is prevalent, and where most of the PTC types are conventional.