Preponderance of the oncogenic V599E and V599K mutations in the B-raf kinase domain is enhanced in melanoma lymph node metastases
Preponderance of the oncogenic V599E and V599K mutations in the B-raf kinase domain is enhanced in melanoma lymph node metastases
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DOI：
10.1097/00008390-200510000-00011
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发表时间：
2005-10-01
影响因子：
2.2
通讯作者：
Deichmann, M
中科院分区：
文献类型：
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作者：
Kirschner, M;Helmke, B;Deichmann, M
据报道，在RAS下游，丝氨酸/苏氨酸激酶B-RAF在原发黑色素瘤的相当大的亚群中发生突变，其中大部分突变位于激活域，包括激活的V599E和V599K转换。我们用聚合酶链式反应(PCR)和单链构象多态(SSCP)凝胶电泳法对54例黑色素瘤淋巴结转移癌切除标本进行了B-RAF激活区(外显子15)突变的检测。对克隆的PCR-SSCP扩增片段进行测序后，发现24例(44%)样本存在体细胞突变，这与最近研究的原发性皮肤黑色素瘤(Deichmann M、Thome M、Benner A、Naher)中发现的突变频率没有显著差异。H.B-RAF外显子15突变在初级黑色素瘤切除标本中很常见，但与临床结果无关。肿瘤学，2004年；66：411-419)。其中20例(83%)存在T1796A激活突变，其次是5例(21%)癌基因g1795A突变。对于B-RAF蛋白序列，在24例阳性转移癌中，分别有15例(62%)和5例(21%)预测到V599E和V599K的酸性氨基酸转变。该热点密码子突变的检测与随后的内脏转移显著相关(P=0.03；Fisher‘s精确检验)。在从原发黑色素瘤(见上文)向淋巴结转移的转变过程中，B-raf基因突变谱显著变窄(P=0.00047)。致癌的B-RAF突变V599E和V599K作为黑素细胞转化的早期事件，持续到转移过程，具有重要的预后意义。
Downstream of Ras, the serine/threonine kinase B-raf has been reported to be mutated, amongst other carcinomas, in a substantial subset of primary melanomas, with a preponderance of mutations within the kinase domain, including the activating V599E and V599K transitions. We investigated a representative series of 54 resection specimens of melanoma lymph node metastases for the presence of mutations within the activation segment (exon 15) of the B-raf kinase domain by polymerase chain reaction (PCR) and single-strand conformational polymorphism (SSCP) gel electrophoresis. Sequencing of cloned PCR-SSCP amplicons resulted in 24 (44%) samples harbouring somatic mutations, which is not significantly different from the mutation frequency found in recently investigated primary cutaneous melanomas (Deichmann M, Thome M, Benner A, Naher H. B-raf exon 15 mutations are common in primary melanoma resection specimens but not associated with clinical outcome. Oncology 2004; 66:411-419). The activating mutation T1796A was present in 20 (83%) of these resection specimens, followed in frequency by the oncogenic g1795A mutation in five (21%) cases. With regard to the B-raf protein sequence, the acidic amino acid transitions V599E and V599K were predicted in 15 (62%) and five (21%) of the 24 positive metastases, respectively. The detection of mutations at this hot spot codon was significantly associated with subsequent visceral metastasis (P = 0.03; Fisher's exact test). During the transition from primary melanomas (see reference above) to lymph node metastases, the spectrum of B-raf mutations narrows significantly (P = 0.00047). The oncogenic B-raf mutations V599E and V599K, as early events in melanocyte transformation, persist throughout metastasis with important prognostic implications.