Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04626 (erbB-2)
 5,251 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The objectives of this study were to examine DNA demethylase (dMTase) expression in ovarian cancers and evaluate methylation of CpG sites in the promoter of the c-erbB-2 gene and survivin gene exon 1. Forty-three epithelial ovarian cancers and 43 non-cancerous ovarian tissues were studied for dMTase expression by RT-PCR. Genomic DNA was extracted and digested with HindIII and then HpaII. CpG site-sensitive primers were constructed to amplify the promoter of the c-erbB-2 gene and survivin gene exon 1. Immunohistochemical evaluation of ErbB-2 protein and RT-PCR for survivin were also performed. dMTase was positive in 88.4% of ovarian cancers but only in 9.3% of non-cancerous ovaries (P<0.001, Fisher's exact test). The expression was similarly observed in both early stage (stage I+II: 17/19) and advanced stage (stage III+IV: 21/24) groups of ovarian malignancy. It was found that 78.9% of dMTase-positive cancers had both c-erbB-2 promoter and survivin gene exon 1 unmethylated, whereas 40% of dMTase-negative cancers had both sites methylated. In non-cancerous ovaries, these sites were mostly methylated (90.6%) and the difference from cancer cases was highly significant (P<0.001). Immunohistochemical evaluation of ErbB-2 showed significant correlation of unmethylated c-erbB-2 promoter and ErbB-2 expression. The RT-PCR for survivin expression showed that 86% of cancers were positive and six cases were negative. Exon 1 was methylated in 83% of the survivin-negative cases. This is the first report of dMTase expression in ovarian cancers. The correlation of dMTase expression with unmethylation of c-erbB-2 promoter and survivin gene exon 1 suggests that these sites may be targets for demethylation by the enzyme. The up-regulation of oncogenes may be the consequence of epigenetic control of gene expression by the dMTase.
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PMID:DNA demethylase is expressed in ovarian cancers and the expression correlates with demethylation of CpG sites in the promoter region of c-erbB-2 and survivin genes. 1143 Nov 4