Department of Medicine and Surgery, University of Salerno, Via Allende 84081, Baronissi, Salerno, Italy.
J Clin Endocrinol Metab. 2012 Jul;97(7):2333-40. doi: 10.1210/jc.2011-3106. Epub 2012 Apr 16.
BRAF(V600E) is considered a negative prognostic marker in papillary thyroid carcinoma (PTC), but unexplained conflicting results are present in the literature. In light of the new finding that most PTC consist of a mixture of tumor cells with wild-type and mutant BRAF, we examined the associations between the percentage of BRAF(V600E) alleles and both the clinicopathological parameters at time of diagnosis and the disease outcome in a large series of PTCs.
Tumors from 168 patients with PTC were genotyped for BRAF(V600E) using BigDye Terminator sequencing and pyrosequencing, and the clinical parameters were analyzed. The associations between clinicopathological characteristics, including disease recurrence at follow-up (median 5.1 yr) and the percentage of mutant BRAF alleles were assessed.
The observed prevalence of BRAF(V600E) was higher when using pyrosequencing then when using BigDye Terminator sequencing (53.6 vs. 36.9%). In the PTC positive for BRAF(V600E), the percentage of mutant alleles ranged from 5.1 to 44.7% of the total BRAF alleles, with a median of 20.6%. The presence or the percentage of BRAF(V600E) alleles did not correlate significantly with sex, multicentricity, lymph node metastasis, or tumor stage. The percentage of BRAF(V600E) alleles directly correlated with age at diagnosis and tumor volume (R(2) = 0.223, P = 0.039, and R(2) = 0.166, P < 0.001, respectively). The percentage of BRAF(V600E) alleles (P = 0.014), tumor volume (P = 0.012), and lymph node metastasis (P = 0.008) predicted the disease outcome. The odds ratio of recurrence for PTC with BRAF(V600E) alleles of 30% or greater, compared with that for PTC with BRAF(V600E) alleles of less than 30%, was 5.31 (P = 0.002).
A high percentage of BRAF(V600E) alleles defines a PTC molecular subtype and predicts a poorer disease outcome. The analysis of BRAF mutations by pyrosequencing is useful to refine the risk stratification of patients with PTC.
BRAF(V600E) 被认为是甲状腺乳头状癌 (PTC) 的不良预后标志物，但文献中存在解释不清的相互矛盾的结果。鉴于新发现大多数 PTC 由野生型和突变型 BRAF 的肿瘤细胞混合组成，我们在一大系列 PTC 中检查了 BRAF(V600E)等位基因的百分比与诊断时的临床病理参数以及疾病结局之间的关联。
使用 BigDye Terminator 测序和焦磷酸测序对 168 例 PTC 患者的肿瘤进行 BRAF(V600E) 基因分型，并分析临床参数。评估了包括随访时疾病复发在内的临床病理特征（中位数 5.1 年）与突变 BRAF 等位基因百分比之间的关联。
使用焦磷酸测序检测到的 BRAF(V600E) 阳性率高于使用 BigDye Terminator 测序（53.6%比 36.9%）。在 BRAF(V600E) 阳性的 PTC 中，突变等位基因的百分比在总 BRAF 等位基因的 5.1%至 44.7%之间，中位数为 20.6%。BRAF(V600E) 等位基因的存在或百分比与性别、多中心性、淋巴结转移或肿瘤分期无显著相关性。BRAF(V600E) 等位基因的百分比与诊断时的年龄和肿瘤体积直接相关（R²=0.223，P=0.039，和 R²=0.166，P<0.001）。BRAF(V600E) 等位基因的百分比（P=0.014）、肿瘤体积（P=0.012）和淋巴结转移（P=0.008）预测疾病结局。与 BRAF(V600E) 等位基因小于 30%的 PTC 相比，BRAF(V600E) 等位基因为 30%或更高的 PTC 的复发比值比为 5.31（P=0.002）。
高百分比的 BRAF(V600E) 等位基因定义了 PTC 的分子亚型，并预测了较差的疾病结局。通过焦磷酸测序分析 BRAF 突变有助于细化 PTC 患者的风险分层。
