| 1 | Methylation profile of the promoter CpG islands of 31 genes that may contribute to colorectal carcinogenesis显示文摘AIM: To establish the methylation profile of the promoter CpG islands of 31 genes that might play etiological roles in colon carcinogenesis.METHODS: The methylation specific PCR in conjunction of sequendng verification was used to establish the methylationprofile of the promoter CpG islands of 31 genes in colorectal cancer (n = 65), the neighboring non-cancerous tissues (n = 5), colorectal adenoma (n = 8), and normal mucosa (n = 1). Immunohistochemically, expression of 10 genes was assessed on the home-made tissue microarrays of tissues from 58 patients. The correlation of tumor specific changes with each of clinical-pathologic features was scrutinized with relevant statistic tools.RESULTS: In comparison with the normal mucosa of the non-cancer patients, the following 14 genes displayed no tumor associated changes: breast cancer 1, early onset (BRCA1), cadherin 1, type 1, E-cadherin (epithelial) (CDH1),death-associated protein kinase 1 (DAPK1), DNA (cytosine-5-)-methyltransferase 1 (DNMT1), melanoma antigen, family A, 1 (directs expression of antigen MZ2-E) (MAGEA1), tumor suppressor candidate 3 (N33), cyclin-dependent kinase inhibitor 1A (p21, Cipl) (p21^WAF1), cyclin-dependent kinase inhibitor 1B (p27, 10pl) (p27^WAF1), phosphatase and tensin hornolog (mutated in multiple advanced cancers 1) (PTEN), retinoic acid receptor, beta (RAR-, Ras association (RaIGDS/AF-6) domain family 1 C (RASSFIC), secreted frizzled-related protein 1 (SFRP1), tissue inhibitor of metalloproteinase 3 (Sorsby fundus dystrophy, pseudoinfiammatory) (TIMP3),and von HippeI-Lindau syndrome (VHL). The rest 17 targets exhibited to various extents the tumor associated changes.As changes in methylation of the following genes occurred marginally, their impact on the formation of colorectal cancer were trivial: adenomatous polyposis coli (APC) (8%, 5165),Ras association (RaIGDS/AF-6) domain family 1A (RASSFIA) (3%, 2/65) and cyclin-dependent kinase inhibitor 2A,alternated reading frame Co14~) (6%, 4/65). The following genes exhibited moderate changes in rnethylation: O-6rnethylguanine-DNA rnethyltransferase (MGMT) (20%, 13/65),rnutL hornolog 1, colon cancer, nonpolyposis type 2 (E. coli) (hMLH1) (18%, 12/65), cyclin-dependent kinase inhibitor 2A (melanoma, p16, inhibits CDK4) P16^NK4a) (10%, 10/65),rnethylated in tumor 1 (MINT1) (15%, 10/65), methylated in tumor 31 (MINT31) (11%, 7/65). The rest changed greatly in the rnethylation pattern in colorectal cancer (CRC): cyclin A1 (cyclin al) (100%, 65/65), caudal type homeobox transcriptdon factor 1 (CDX1) (100%, 65/65), RAR(85%, 55/65), myogenic factor 3 (MYOD1) (69%, 45/65),cyclin-dependent kinase inhibitor 2B (p15, inhibits CDK4)(p15^INK4b) (68%, 44/65), prostaglandin-endoperoxide synthase 2 (prostaglandin G/H synthase and cyclooxygenase) (COX2) (72%, 47/65), cadherin 13, H-cadherin (heart) (CDH13) (65%, 42/65), CAAX box 1 (OO~/) (58%, 38/65),tumor protein p73 (p73) (63%, 41/65) and Wilrns tumor 1 (WT/) (58%, 38/65). However, no significant correlation of changes in rnethylation with any given clinical-pathological features was detected. Furthermore, the frequent changes in rnethylation appeared to be an early phase event of colon carcinogenesis. The in situ expression of 10 genes was assessed by the irnrnunohistochernical approach at the protein level: CDH1, CDH13, COX2, cyclin A1, hMLH1,MGMT, p14^ARF, p73, RAR-, and TIMP3 genes in the context of the rnethylation status in colorectal cancer. No clear correlation between the hyperrnethylation of the promoter CpG islands and the negative expression of the genes was established.CONCLUSION: The methylation profile of 31 genes was established in patients with colon cancer and colorectal adenornas, which provides new insights into the DNA rnethylation mediated mechanisms underlying the carcinogenesis of colorectal cancer and may be of prognostic values for colorectal cancer. | Xiao-UXu JianYu Hong-YuZhang Meng-HongSun JunGu XiangDu Da-RenShi PengWang Zhen-HuaYang Jing-DeZhu | 2004 | World Journal of Gastroenterology2004，10，23： | 43 |
| 2 | C-kit gene mutation in human gastrointestinal stromal tumors显示文摘AIM: TO investigate the significance of c-kit gene mutation in gastrointestinal stromal tumors (GIST).METHODS: Fifty two cases of GIST and 28 cases of other tumors were examined. DNA samples were extracted from paraffin sections and fresh blocks. Exons 11, 9 and 13 of the c-kit gene were amplified by PCR and sequenced.RESULTS: Mutations of exon 11 were found in 14 of 25 malignant GISTs (56%), mutations of exon 11 of the c-kit gene were revealed in 2 of 19 borderline GISTs (10.5%),and no mutation was found in benign tumors. The mutation rate showed significant difference (x^2=14.39, P<0.01) between malignant and benign GISTs. Most of mutations consisted of the in-frame deletion or replication from 3 to 48 bp in heterozygous and homozygous fashions, None of the mutations disrupted the downstream reading frame of the gene. Point mutations and frame deletions were most frequently observed at codons 550-560, but duplications were most concentrated at codons 570-585. No mutations of exons 9 and 13 were revealed in GISTs, Neither c-kit gene expression nor gene mutations were found in 3 leiomyomas, 8 leiomyosarcomas, 2 schwannomas, 2 malignant peripheral nerve sheath tumors, 2 intra-abdominal fibromatoses, 2 malignant fibrous histiocytomas and 9 adenocarcinomas.CONCLUSION: C-kit gene mutations occur preferentially in malignant GISTs and might be a clinically useful adjunct marker in the evaluation of GISTs and can help to differentiate GISTs from other mesenchymal tumors of gastrointestinal tract, such as smooth muscle tumors,schwannomas, etc. | Ying-YongHou Yun-ShanTan Meng-HongSun Yong-KunWei Jian-FangXu Shao-HuaLu Su-JieA-Ke-Su Yan-NanZhou FengGao Ai-HuaZheng Tai-MingZhang Wen-ZhongHou JianWang XiangDu Xiong-ZengZhu | 2004 | World Journal of Gastroenterology2004，10，9： | 3 |
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