Brain Tumors Research Today is a free monthly online journal that collates and summarizes the latest research about Brain Tumors, including details on symptoms, benign and malignant tumors, gliomas, screening, treatment. | ||||||||
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Genetic alteration and expression of the phosphoinositol-3-kinase/Akt pathway genes PIK3CA and PIKE in human glioblastomas.Knobbe CB, Trampe-Kieslich A, Reifenberger G Department of Neuropathology, Heinrich-Heine-University, Düsseldorf, Germany. Glioblastomas frequently carry genetic alterations resulting in an aberrant activation of the phosphoinositol-3-kinase (Pi3k)/protein kinase B (Akt) signalling pathway, including most notably phosphatase and tensin homolog (PTEN) mutation, epidermal growth factor receptor (EGFR) amplification and rearrangement, as well as carboxyl-terminal modulator protein (CTMP) hypermethylation [Knobbe et al., (2004) Hypermethylation and transcriptional downregulation of the carboxyl-terminal modulator protein gene in glioblastomas. J Natl Cancer Institute, 96, 483-486]. Here, we investigated two further Pi3k/Akt pathway genes, namely PIK3CA (3q26.3) and phosphatidylinositol-3-kinase enhancer (PIKE) (CENTG1, 12q14), for genetic alteration and aberrant expression in a series of 97 primary glioblastomas. Single strand conformation polymorphism (SSCP) analysis of PIK3CA revealed somatic mutations in five tumours (5%). Twelve glioblastomas (12%) showed amplification of PIKE with invariable co-amplification of the adjacent CDK4 gene. All tumours with PIKE amplification as well as the vast majority of glioblastomas without amplification demonstrated increased expression of PIKE-A but not PIKE-S/L transcripts as compared with non-neoplastic brain tissue. Taken together, our data support an important role of PIK3CA and PIKE gene aberrations in the molecular pathogenesis of primary glioblastomas. Published 9 September 2005 in Neuropathol Appl Neurobiol, 31(5): 486-90.
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