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Global profiling of methylation status in lung cancer tissues.
Keshava N; Huffman D; Wu ZL; Ong T
Environ Mol Mutagen 2002 Jan; 39(Suppl 33):35
Aberrant DNA methylation pattern is an acquired epigenetic alteration causing inappropriate activation or silencing of a gene. Alterations in DNA methylation, mainly occurring in the CpG islands located in the 5' regulatory regions of genes, have been associated with cancers and represent one of the most consistent changes in neoplastic cells. To determine if alterations in global methylation may contribute to the development of lung cancer, we studied genome-wide aberrant methylation pattern in tissues obtained from 57 lung cancer cases. Methylation was carried out using methylation sensitive restriction DNA fingerprinting analysis. BstU1 (sensitive enzyme for cytosine methylation at CpG site) and Mse1 (non-sensitive enzyme for cytosine methylation) were used for restriction analysis. We found that 86% of all the lung cancer tissues were hypermethylated at various sites using short random primers. Many fragments appeared to be differentially methylated. Upon sub-cloning, sequencing and matching several common differentially methylated fragments using the available database (BLAST), we have identified the fragments to encode for human cyclin C(CCNC). Wilms tumor (WT-1) and nuclear factor-kappa B (NF-kB) genes. Analysis of fragments among tumor types revealed that 49% of the hypermethylated fragments were adenocarcinomas, 30% were squamous cell carcinomas and 21% belonged to other types. When age or sex was considered as a factor, no significant difference in any of these groups was observed. Methylation pattern was unrelated to smoking status of the patients. Our overall results indicate that hypermethylatlon seems to play an important role in the development of lung cancer. Further studies are in progress to elucidate the molecular mechanism(s) of hypermethylation in lung cancer.
Genes; Carcinogenicity; Carcinogens; Carcinogenesis; Lung-disease; Lung-disorders; Lung-lesions; Lung-tissue; Tissue-culture; Tissue-disorders; Pulmonary-cancer; Pulmonary-disorders; Pulmonary-system; Pulmonary-system-disorders
Research Tools and Approaches: Cancer Research Methods
Environmental and Molecular Mutagenesis
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