脑肿瘤抑癌基因研究进展

癌症的发展是一个复杂和多步骤的过程,在这个过程中一系列进行性改变导致体细胞的失控性增殖。癌细胞的特征是能够无约束地生长,能够侵袭到周围正常的组织,并能够转移到远处的器官。大多数肿瘤,包括神经系统的肿瘤,都是原发的。改变后细胞的遗传学破坏可能是由于遗传中的倾向性,细胞周期中DNA重排,病毒感染和整合;也可能是暴露在突变因子情况下,诸如离子辐射一类,这些因素可以使癌细胞的生长优于它的正常部分。通常广谱的肿瘤遗传学改变包括两类基因的改变:第一,癌基因的优势,它的出现导致细胞的改变;第二,隐性抗癌基因的缺乏,它的缺乏引起细胞的改变。后者通常又称为肿瘤抑制基因,生长抑制基因或隐性抗癌基因。可以相信正常细胞的增殖是在这些促进生长的原癌基因和抑制生长的抗癌基因的内在控制下进行的突变、重排、缺失或扩增而潜在地激活原癌基因导致肿瘤的形成。同样的事件可以发生在抗癌基因和抑癌基因的失活,干扰它们在细胞中作为细胞增殖的负性调控作用。本文主要介绍在GenBank中登录的与人脑肿瘤相关的抑癌基因的情况。

Current Progress on Study of Tumor Suppressor Genes in Brain Tumors

The development of cancer is a complicated and multistep process in which a series of progressive changes culminates in deregulation of cell proliferation in somatic cells. Cancer cells are characterized by unconstrained cell growth, ability to invade surrounding normal tissues, and to metastasize to distant organ sites. Most neoplasms, including tumors in nervous system, are clonal in origin. The genetic damage in transformed cells is due to either inherited predisposition DNA rearrangements during the cell cycle, viral infection and integration, or exposure to mutational agents such as ionizing radiation. These sources induce alterations that confer a growth advantage to the cell over its normal counterpart; In general, genetic changes in a broad spectrum of neoplasms including the alteration of two classes of genes: dominant oncogenes, the presence of which causes cellular transformation, and recessive antioncogenes, the absence of which causes cellular transformation. The latter has been also commonly called tumor suppressor gene, growth suppressor gene, or recessive antioncogene. It is believed that normal cell proliferation is under the intrinsic control of these growth-promoting proto-oncogenes and growth-constraining anti-oncogenes. Mutations, rearrangements, deletions, or amplifications that potentiate the activities of protooncogenes so that results in tumor formation. Similar events that inactivate anti-oncogenes or suppressor genes disrupt their role in the cell as negative regulators of cell growth and proliferation. This artical focused on discussing the tumor suppressor genes relating to human brain tumor which were released on GenBank.