engleski

Genetic changes of the Wnt pathway components found in brain tumors

Research carried out in this paper deals with the molecular characterisation of E-cadherin (CDH-1), beta-catenin (CTNNB1) and adenomatous polyposis coli (APC) genes in a panel of 50 central nervous system tumors. All genes are involved in the Wnt signalling pathway. Beta-catenin is the main downstream effector of the Wnt signalling. E-cadherin is associated with β -catenin and plays a role in cell-cell adhesion, while APC protein also plays a signalling role as a negative regulator of the wnt pathway. Our interest in genes of the wnt pathway stemmed principally from the findings that wild-type APC protein is highly expressed in the central nervous system, and upon the finding that it is involved in particular syndromes, among which the brain tumors play a significant role. Brain tumor samples were tested for gene instability of the APC gene by PCR/loss of heterozygosity using RFLP method. PCR amplification of tetranucleotide GATA polymorphism (D16S752) was used to test loss of heterozygosity of the E-cadherin gene. Changes of beta-catenin were tested by heteroduplex method. The results of our analysis showed allelic loss of the APC gene in 33.3% of glioblastomas. Another 23.8% of samples demonstrated allelic imbalance. Altogether, there were 12 samples (57%) demonstrating instability of APC gene confined to glioblastomas. Twenty five percent of meningeomas showd LOH of CDH1 gene. One LOH of this gene was found in germinoma and one in teratoma. Heteroduplex method revealed 3 samples with additional bands indicating possible mutations in exon 3 of the beta-catenin gene. Mutations of β -catenin were confined to a meningeoma, a glioblastoma and a germinoma. Our findings on genetic changes of the wnt components may contribute to better understanding of brain tumors genetic profile and could be used as prognostic marker of disease evolution and progression.

wnt pathway; brain tumors

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