Hypermethylation of the DNA mismatch repair gene hMLH1 and its association with lymph node metastasis and T1799A BRAF mutation in patients with papillary thyroid cancer.
We analyzed the expression of S100A4, cyclin D1, p27 and MUC1, the presence of the BRAF V600E mutation and the clinicopathological features of the tumors, including patient age, tumor size (>or=5 vs <5 mm), extrathyroidal extension, multifocality, histological subtype, sclerosis and encapsulation, in a series of 198 papillary microcarcinomas in relation to lymph node metastasis to determine the predictive factors of lymph node metastasis.
Tumor size correlated significantly with multifocality, extrathyroidal extension, and lymph node metastasis (P = 0.003, P < 0.001 and P < 0.001, respectively), but the BRAF V600E mutation status was not associated with any of those features.
On univariate analysis, the BRAF(V600E) mutation was associated with extrathyroidal extension (P = .009) and variants of PTC (P = .019), but a high-risk Metastasis, Patient Age, Completeness of resection, local Invasion and Tumor Size (MACIS) score (≥ 6) (P = .146) and lymph node metastasis (P = .628) were not significantly associated with the BRAF(V600E) mutation.
In a series of 33 cases, 21 harbored the T1799A mutation in the primary tumors, and 17 (81%) of them harbored the same mutation also in the paired lymph node metastases.
BRAF(V600E) mutation-positive cancers (55.3%) were more frequently associated with lymph node metastasis (p=0.01) and advanced TNM stage (III-IV) (p=0.03).
In thyroid cancer, the V600E mutation occurs with greater frequently in aggressive subtypes of PTC, and in individuals that present at advanced stages of disease with extra-thyroidal extension and/or lymph node metastases.
There was no statistically significant correlation in age, gender, multifocality, extrathyroidal extension, presence of Hashimoto thyroiditis, and lymph node metastasis between the BRAF(V600E) mutant group and wild group.
The BRAF(V600E) mutation was significantly associated with age (≥ 45 years), tumor size (>1 cm), extrathyroidal extension, and cervical lymph node metastases (P < 0.05).
The BRAF c.1799T>A (p.Val600Glu) substitution was present in 59.0% Chinese PTCs, more frequently observed in patients with lymph node metastasis (P = 1.6 × 10(-4)).
Compared with wild-type BRAF, the BRAF(V600E) mutation was associated with aggressive clinicopathological factors, including extrathyroidal extension, higher TNM stage, lymph node metastasis, and recurrence, and was associated with reduced overall survival; however, there was no significant association between the presence of BRAF mutation and distant metastasis.
Considering all tumor foci, the all BRAF(V600E) mutation group exhibited a younger population (P = .039), showed increased extrathyroidal invasion (38.8% vs 14.7%, P = .017) and lymph node metastasis (71.4% vs 48.4%, P = .038), and received more radioactive iodine therapy (79.2% vs 52.9%, P = .012) than the mixed BRAF(V600E) mutation group.
No significant differences were observed in either the occurrence or the allele percentage of V600E mutation between the 2 groups of PTCs with or without LNMs.
We report a 65-year-old woman with anaplastic thyroid carcinoma (BRAF V600E mutation) who had lymph node metastases (pT4 N1b) treated by total thyroidectomy, postoperative radiotherapy, adjuvant chemotherapy (paclitaxel and pazopanib) and targeted therapy (vemurafenib).
In patients with conventional papillary thyroid cancer, BRAF V600E mutation was associated with older age (P = 0.0381), lymph node metastasis (P = 0.0323), distant metastasis (P = 0.045), higher TNM stage (I and II vs. III and IV, P = 0.0389), and recurrent and persistent disease (P = 0.009) with a median follow-up time of 6.0 years.