Yamamoto Takahiro, Shinojima Naoki, Todaka Tatemi, Nishikawa Shigeyuki, Yano Shigetoshi, Kuratsu Jun-ichi
Division of Neurosurgery, Nobeoka Hospital, Miyazaki, Japan; Department of Neurosurgery, Kumamoto University Hospital, Kumamoto, Japan.
Department of Neurosurgery, Kumamoto University Hospital, Kumamoto, Japan.
World Neurosurg. 2015 Sep;84(3):866.e1-6. doi: 10.1016/j.wneu.2015.03.065. Epub 2015 Apr 9.
Down syndrome comprises multiple malformations and is due to trisomy of chromosome 21. There is epidemiologic evidence that individuals with Down syndrome are at decreased risk for solid tumors including brain tumors. It has been suggested that some genes expressed on the extra copy of chromosome 21 act as tumor suppressor genes and contribute to protection against tumorigenesis.
We report the first case to our knowledge of a patient with Down syndrome, an 8-year-old boy, with an intracranial meningioma, in which the status of chromosome 21 was examined. The diagnosis was based on histologic examination of the surgically resected tumor. Postoperatively, the patient's neurologic status improved, and there was no tumor regrowth in the next 2 years. Fluorescence in situ hybridization for chromosome 22 confirmed high allele loss involving the neurofibromin 2 gene locus, a finding typical in meningiomas. Fluorescence in situ hybridization also revealed chromosome 21 heterogeneity in tumor cells; not only cells with trisomy 21 but also cells with disomy and monosomy 21 were present. All blood cells from the patient manifested trisomy 21.
Deletion of the chromosome 21 allele may be associated with tumorigenesis of meningioma in Down syndrome. This supports the hypothesis that some genes whose expression is increased on the extra copy of chromosome 21 function as tumor suppressor genes and that they contribute to the reduced tumor incidence in individuals with Down syndrome.
唐氏综合征包含多种畸形，由21号染色体三体所致。有流行病学证据表明，唐氏综合征患者患实体瘤（包括脑肿瘤）的风险降低。有人提出，21号染色体额外拷贝上表达的一些基因充当肿瘤抑制基因，有助于预防肿瘤发生。
据我们所知，我们报告了首例患有唐氏综合征的颅内脑膜瘤患者，这是一名8岁男孩，我们对其21号染色体状态进行了检查。诊断基于手术切除肿瘤的组织学检查。术后，患者的神经状态有所改善，且在接下来的2年中无肿瘤复发。22号染色体荧光原位杂交证实神经纤维瘤病2基因位点存在高等位基因缺失，这是脑膜瘤中的典型发现。荧光原位杂交还显示肿瘤细胞中21号染色体存在异质性；不仅有21号染色体三体的细胞，还有21号染色体二体和单体的细胞。患者的所有血细胞均表现为21号染色体三体。
21号染色体等位基因的缺失可能与唐氏综合征患者脑膜瘤的发生有关。这支持了以下假设，即21号染色体额外拷贝上表达增加的一些基因起到肿瘤抑制基因的作用，并且它们有助于降低唐氏综合征患者的肿瘤发生率。
