Department of Clinical and Experimental Medicine and Surgery, Endocrine Unit, Second University of Naples, Naples, Italy.
Thyroid. 2011 Apr;21(4):391-9. doi: 10.1089/thy.2010.0168.
Endocrine gland-derived vascular endothelial growth factor (Prok1) and prokineticin 2 (Prok2) are involved in the organ-specific regulation of angiogenesis, which is a crucial step toward cancer progression in most tumors, including those of thyroid gland. The oncogene BRAF V600E mutation is associated with poor clinical outcome of papillary thyroid cancer (PTC) and can independently predict its recurrence.
Our hypothesis was that Prok1 and Prok2 expression levels associated with BRAF mutations can be prognostic factors for PTC outcome. Prok1 and Prok2 were examined in PTC, a cell line derived from a human PTC (designated FB-2), euthyroid multinodular goiter (MNG), Graves' disease (GD), and contralateral normal thyroid (NT) tissues from PTC cases. We evaluated BRAF mutation and its relationship with Prok1 expression pattern in PTC.
We studied Prok1 and Prok2 mRNAs by real-time polymerase chain reaction and BRAF mutation by mutant allele-specific polymerase chain reaction amplification. Formalin-fixed, paraffin-embedded blocks of PTC and NT were used for the immunohistochemical determination of Prok1 using anti-endocrine gland vascular endothelial growth factor primary antibody.
Prok1 and Prok2 transcripts were both present in thyroid tissues, and Prok1 was differentially expressed in PTC compared to MNG, GD, and NT. Prok1 mRNA levels were very low in NT and MNG and significantly higher in PTC, FB-2, and GD (p<0.05). Prok1 protein was almost undetectable in NT but was highly expressed in all PTC samples having an infiltrative pattern of growth and lymph node metastases ( p<0.05). Further, the expression of Prok1 in PTC was associated with 60% of the samples being positive for the BRAF mutation ( p<0.05).
We found that Prok1 is significantly increased in PTC, and its expression in PTC is related to BRAF mutation. These results suggest that Prok1 could be a new useful marker for thyroid cancer progression. Prok1 therefore could also be a potential target for novel therapeutic strategies, although the lack of functional data suggests caution against generalization of this assumption
内分泌腺衍生的血管内皮生长因子（Prok1）和促动力素 2（Prok2）参与血管生成的器官特异性调节，这是大多数肿瘤（包括甲状腺肿瘤）向癌症进展的关键步骤。BRAF V600E 突变是甲状腺乳头状癌（PTC）不良临床结局的相关因素，并且可以独立预测其复发。
我们的假设是，与 BRAF 突变相关的 Prok1 和 Prok2 表达水平可以作为 PTC 结局的预后因素。我们检测了 PTC、源自人 PTC（命名为 FB-2）的细胞系、甲状腺功能正常的多结节性甲状腺肿（MNG）、Graves 病（GD）和 PTC 病例对侧正常甲状腺（NT）组织中的 Prok1 和 Prok2。我们评估了 PTC 中的 BRAF 突变及其与 Prok1 表达模式的关系。
我们通过实时聚合酶链反应检测 Prok1 和 Prok2 mRNA，并通过突变等位基因特异性聚合酶链反应扩增检测 BRAF 突变。我们使用抗内分泌腺血管内皮生长因子的一抗，通过福尔马林固定、石蜡包埋的 PTC 和 NT 块，对 Prok1 进行免疫组织化学测定。
Prok1 和 Prok2 转录本均存在于甲状腺组织中，与 MNG、GD 和 NT 相比，Prok1 在 PTC 中差异表达。Prok1 在 NT 和 MNG 中的水平非常低，而在 PTC、FB-2 和 GD 中显著升高（p<0.05）。Prok1 蛋白在 NT 中几乎检测不到，但在所有具有浸润性生长和淋巴结转移的 PTC 样本中高度表达（p<0.05）。此外，PTC 中 Prok1 的表达与 60%的样本 BRAF 突变阳性相关（p<0.05）。
我们发现 Prok1 在 PTC 中显著增加，其在 PTC 中的表达与 BRAF 突变相关。这些结果表明 Prok1 可能是甲状腺癌进展的一个新的有用标志物。Prok1 因此也可能成为新的治疗策略的潜在靶点，尽管缺乏功能数据表明对这一假设应谨慎推广。
