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| Untersuchte Arbeit: Seite: 13, Zeilen: 1-3, 6-20 |
Quelle: Waelzlein 2007 Seite(n): 13, 14, Zeilen: 13: 10ff; 14: 1ff |
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| [Very well known are] mutations in the tumor suppressor gene p53 on chromosome 9, which also plays a pivotal role in other types of cancer. In fact, only about a third of glioblastomas carries this mutation, which corresponds to the percentage in lower grade gliomas. [...] This suggests that the p53 gene is involved rather early in neoplastic transformation (Kleihues, P., et al, 1993). In about one third of all GBMs one can find amplification and mutation of the endothelial growth factor receptor gene (EGFR) like EGFRvIII which is the mutant version of EGFR in Glioblastoma multiforme mutation which leads to increased cell proliferation. Furthermore platelet-derived growth factor alpha (PDGF-α) and phosphatase and tensin homolog deleted on chromosome ten (PTEN) are two more genes, of which the expression is altered in GBMs (Knobbe,C.B. et al, 2002; Nakamura, J.L. et al, 2007). PDGF-α belongs to the family of growth factors and is involved in the regulation of cell growth and cell division. It plays a particular role in angiogenesis, which is characteristically increased in cancer to provide sufficient nutrition supply for the tumor. The phosphatase PTEN is a tumor suppressor, which is related to a variety of biological functions like apoptosis, inflammation and immunity. These genetic defects have an effect on other cell proteins and finally result in tumor formation. | Very well known are mutations in the tumour suppressor gene p53 on chromosome 9, which also plays a pivotal role in other types of cancer. In fact, only about one third of glioblastomas carries this mutation, which corresponds to the percentage in lower grade gliomas. This suggests that the p53 gene is involved rather early in neoplastic transformation (40). In about one third of all GBMs one can find amplification of the endothelial growth factor receptor gene (EGFR), which leads to increased cell proliferation. Furthermore platelet-derived growth factor alpha (PDGF-α) and phosphatase and tensin homolog (PTEN) are two more genes, of which the expression is altered in GBMs (42;52). PDGF-α belongs to the family of growth factors and is
[Seite 14] involved in the regulation of cell growth and cell division. It plays a particular role in angiogenesis, which is characteristically increased in cancer to provide sufficient nutrition supply for the tumour. The phosphatase PTEN is a tumour suppressor, which is related to a variety of biological functions like apoptosis, inflammation and immunity. These genetic defects have an effect on other cell proteins and finally result in tumour formation. 40. Kleihues,P., Burger,P.C., and Scheithauer,B.W. 1993. The new WHO classification of brain tumours. Brain Pathol. 3:255-268. 42. Knobbe,C.B., Merlo,A., and Reifenberger,G. 2002. Pten signaling in gliomas. Neuro.-oncol. 4:196-211. 52. Nakamura,J.L. 2007. The epidermal growth factor receptor in malignant gliomas: pathogenesis and therapeutic implications. Expert.Opin.Ther.Targets. 11:463-472. |
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