Prognostic Relevance of Transforming Genes

摘要: Malignant transformation is considered the result of a multipstep process in which cells aquire mutations genes that are critical for regulation cell proliferation and differentiation (Bishop 1987; Weinberg 1989). In astrocytic gliomas several different have been identified, some confined to certain grades malignancy (Collins 1990). Amplification overexpression gene encoding epidermal growth factor receptor (EGFR) nearly exclusively present glioblastomas (Libermann 1985; Ekstrand 1991; Agosti 1992). EGFR fragments with large deletions truncated has described as well amplification intact functional (Yamazaki 1988; Humphrey 1990,1991; An amplified overexpressed may or not be capable being activated by its main ligand transforming factor-α (TGF-α; Yamazaki 1991). many TGF-α itself found number these tumors without evidence genetic alteration (Schlegel 1990; 1991), an autocrine mechanism stimulation EGFR/TGF-α system postulated glioma (Ekstrand Mutations allelic loss tumor suppressor p53 reported (Nigro 1989; v. Deimling 1992; Frankel Fults It low-grade astrocytomas represent minority. The fact undergo clonal expansion recurrent malignant suggests play significant role progression (Sidransky