Akbasak A, Sunar-Akbasak B
Clinical Neurosurgery Section, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892.
J Neurol Sci. 1992 Sep;111(2):119-33. doi: 10.1016/0022-510x(92)90060-x.
Recent developments in the field of oncogenes and growth stimulatory factors have provided limited but essential models in neuro-oncology. The observation in gliomas of platelet growth factor (PDGF)-like immunoreactivity fits with the autocrine secretion model, rising the possibility for the growth factor independence of the cancer cells. The discovery of the tumor suppressor genes, for which loss of function mutations are oncogenic as in the RB gene of the retinoblastoma and p53 gene, has introduced a new concept of oncogenesis which could be useful even in the cure of the neoplasms. Several oncogenes are amplified and/or expressed in brain tumors, some associated with polymorphism leading to abnormal protein products. Therefore, corresponding functions, such as production of deficient epidermal growth factor receptor (EGFR) encoded by erb-B, are impaired. Abnormal chromosomal patterns have been recognized in brain tumors and found mainly in chromosomes 7 and 22 on which oncogenes erb-B and sis are located, respectively. Location of proto-oncogenes, which are normally expressed in the brain, indicate that they share common distribution patterns mainly involving the cerebellum, hippocampus and olfactory bulbs. These proto-oncogenes may be regulated by physiological and pathological events. The concept of oncogene involvement in brain tumors must be extended to include the other factors such as G-proteins, growth factor receptors, membrane-associated and cytoplasmic protein kinases, which are all responsible for the control of the cell growth and their response to external signals including chemotherapeutic drigs.
癌基因与生长刺激因子领域的最新进展为神经肿瘤学提供了有限但至关重要的模型。在胶质瘤中观察到血小板生长因子（PDGF）样免疫反应性，这与自分泌模型相符，增加了癌细胞生长因子独立性的可能性。肿瘤抑制基因的发现，其功能丧失突变如视网膜母细胞瘤的RB基因和p53基因一样具有致癌性，引入了一种新的肿瘤发生概念，这甚至可能对肿瘤的治疗有用。几种癌基因在脑肿瘤中被扩增和/或表达，一些与导致异常蛋白质产物的多态性相关。因此，相应的功能，如由erb - B编码的表皮生长因子受体（EGFR）产生不足，会受到损害。脑肿瘤中已识别出异常染色体模式，主要发现于分别携带癌基因erb - B和sis的7号和22号染色体上。通常在脑中表达的原癌基因的定位表明它们具有共同的分布模式，主要涉及小脑、海马体和嗅球。这些原癌基因可能受生理和病理事件调控。癌基因参与脑肿瘤的概念必须扩展到包括其他因素，如G蛋白、生长因子受体、膜相关和细胞质蛋白激酶，它们都负责控制细胞生长及其对包括化疗药物在内的外部信号的反应。
