Department of Medical Biology and Genetics, Dokuz Eylul University, School of Medicine, Izmir, Turkey.
Cancer Lett. 2012 Apr 1;317(1):72-7. doi: 10.1016/j.canlet.2011.11.013. Epub 2011 Nov 13.
Somatic and germline mutations of the anaplastic lymphoma kinase (ALK) gene were recently described in neuroblastoma (NB). In this study, we investigated the association of ALK copy number alterations with copy number status 2p24.1 amplicon harboring DEAD box polypeptide 1 (DDX1), MYCN and neuroblastoma-amplified (NAG) genes in 90 primary tumors of sporadic NB cases by multiplex ligation-dependent probe amplification (MLPA). We also performed mutation analysis of ALK gene by directly sequencing the exons 20-28 which cover the region that encodes juxtamembrane and kinase domains. A total of 39 (43.3%) NB cases revealed copy numbers alterations of ALK gene. There was highly significant association of ALK copy number gains with gains of one or more of the genes at 2p24.1 (DDX1, MYCN or NAG) in MYCN unamplified tumors (P<0.000). In addition, 15 of 17 MYCN amplified cases (88.2%) had aberrant ALK status. Solitary gain of ALK with normal copy number status of all other genes was observed only in one case. DNA sequencing of exons 20-28 of ALK revealed two different nucleotide changes in three cases leading to amino acid substitutions of F1245V and R1275Q in tyrosine kinase domain. In conclusion, the frequency of ALK mutations in NB is low and solitary copy number change of it is rarely observed.
ALK 基因的体细胞和种系突变最近在神经母细胞瘤 (NB) 中被描述。在这项研究中，我们通过多重连接依赖性探针扩增 (MLPA) 检测了 90 例散发性 NB 原发肿瘤中 ALK 拷贝数改变与 2p24.1 扩增子中 DEAD 框多肽 1 (DDX1)、MYCN 和神经母细胞瘤扩增 (NAG) 基因的拷贝数状态之间的关联。我们还通过直接测序外显子 20-28 对 ALK 基因进行了突变分析，该区域编码跨膜区和激酶结构域。共有 39 例 (43.3%) NB 病例显示 ALK 基因拷贝数改变。在 MYCN 未扩增的肿瘤中，ALK 拷贝数增加与 2p24.1 上一个或多个基因 (DDX1、MYCN 或 NAG) 的获得高度相关 (P<0.000)。此外，17 例 MYCN 扩增病例中有 15 例 (88.2%) 存在异常 ALK 状态。仅在 1 例中观察到 ALK 单独获得，而所有其他基因的拷贝数均正常。ALK 外显子 20-28 的 DNA 测序显示，在 3 例中发现了两种不同的核苷酸变化，导致酪氨酸激酶结构域中的 F1245V 和 R1275Q 氨基酸取代。总之，NB 中 ALK 突变的频率较低，很少观察到其单独的拷贝数改变。
