| SummaryPurpose:1. Systemic analysis of copy number variations (CNVs) and loss of heterozygosity (LOH) in sporadic pheochromocytoma cells genome DNA,discovery tumor-related changes of copy number and and loss of heterozygosity where chromosomal location, screening pheochromocytoma tumor-associated genes or molecular markers to provide a new reference. for the diagnosis of pheochromocytoma and treatment. 2. Analysis the differences of selected gene's m-RNA expression level between benign and malignant pheochromocytomas,look for molecular genetics markers for the diagnosis of benign and malignant pheochromocytoma, and to prove SNP array is an effective method of screening the tumor-related genes.Materials and methods:1. Apply Affymetrix Inc. GeneChip SNP 6.0 chip to detect whole genome DNA copy number variations (including amplification and deletion) and LoH in 5 cases of pheochromocytoma (including tumor tissue and their own peripheral blood leucocyte).2. Analysis of SNP 6.0 chip test results; screening CNV or LoH region,and find the pheochromocytoma tumor-related genes.3.29 patients dignosised as pheochromocytoma from 2000 to 2008 in PUMCH were enrolled. including 19 cases of benign and 10 cases of malignant, Take another 12 cases of normal adrenal medulla tissue as normal control group. Extract cell DNA and apply Real time quantitative PCR (real-time PCR) to detect candidate genes m-RNA expression level in each group.4. Statistical analysis of candidate gene m-RNA expression levels in different histological types of(benign/malignant) adrenal tumor.discovery the relationship between candidate genes expression levels with Pathological classification and prognosis of pheochromocytomaResults: 1.5 cases of pheochromocytoma tissue compared with matched normal cells,5 cases of chromosome deletion occurred in 1p21.1-1p21.2; 4 cases of pheochromocytoma occurring deletion of chromosome 1p is mainly,3q and 11p.2.5 cases of pheochromocytoma cells compared with matched normal cells,4 cases of pheochromocytoma occurring mainly amplification of chromosome 5q.3.5 cases of pheochromocytoma cell compared with matched normal cells, all cases of pheochromocytoma have undergone LOH.4 cases had chromosomes 1p, 11p, 11q of LOH, common regional and gene:11p15.13 and SOX6; 3 cases had chromosome 5q of LOH, common regional and gene:5q31.3 and NRG2; 2 cases had chromosome 3p,6q of LOH.4. Common occurrence in the three cases of chromosome 5q31.3 LoH containing the NRG1 gene,NRG1 gene and its homologous gene NRG2 was selected as candidate genes.5. NRG2-mRNA was expressed in benign pheochromocytoma, malignant pheochromocytoma and normal adrenal medulla tissue. was significantly lower in pheochromocytoma than in the adrenal medulla (P<0.01); but had no significant difference between benign and malignant pheochromocytoma group (P> 0.05). NRG1-mRNA expression in malignant pheochromocytomas was significantly higher than in benign pheochromocytomas (P<0.05)。Conclusion:1. SNP6.0 chip can effectively detect and precisely locate pheochromocytoma whole-genome small area DNA copy number changes and LoH, can discover new CNV regions of chromosomes.2. deletion or amplification of DNA may occur with tumor development, which may be the basis of tumor pathogenesis. Test results for further screening and localization of pheochromocytoma-related genes provide important clues and theoretical information.3. NRG2 m-RNA expression reduced in pheochromocytoma may be basis of the existence of chromosome NRG2 LoH, which may be involved in the development of pheochromocytoma molecular mechanisms; NRG1-mRNA expression level in malignant pheochromocytoma was significantly higher than the expression of benign pheochromocytoma, can be used as molecular markers for malignant pheochromocytoma, and as pheochromocytoma prognosis factor.4. SNP chips is an effective method of screening pheochromocytoma tumor-associated genes...
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