DNA methylation of multiple tumor-related genes in association with overexpression of DNA methyltransferase 1 (DNMT1) during multistage carcinogenesis of the pancreas
DNA methylation of multiple tumor-related genes in association with overexpression of DNA methyltransferase 1 (DNMT1) during multistage carcinogenesis of the pancreas
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DOI：
10.1093/carcin/bgi361
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发表时间：
2006-06-01
期刊：
影响因子：
4.7
通讯作者：
Hirohashi, Setsuo
中科院分区：
文献类型：
--
作者：
Peng, Dun-Fa;Kanai, Yae;Hirohashi, Setsuo
为了评价胰腺多阶段癌变过程中DNA甲基化改变的意义，13例无明显组织学变化且无炎症背景（DE）的外周胰管上皮组织样品，20例无明显组织学变化且有炎症背景（DEI）的外周胰管上皮组织样品，从58例患者的手术切除标本中显微解剖40例胰腺上皮内瘤变（PanIN）和147例导管癌，并包埋在琼脂糖珠中。采用甲基化特异性PCR（MSP）检测p14、p15、p16、p73、APC、hMLH 1、MGMT、BRCA 1、GSTPI、TIMP-3、CDH 1和DAPK-1基因的甲基化状态。在DEI组和对照组中，12个基因中至少有一个基因的DNA甲基化发生率和甲基化基因的平均数均显著高于对照组和对照组。（分别为60%和0.85 +/- 0.88，P = 0.0151和P = 0.0224）和PanIN（分别为67.5%和0.95 ± 0.85，P = 0.0014和P = 0.0028）乳腺导管癌中分别为98.3%和2.50 ± 1.35（P < 0.0001和P < 0.0001）。乳腺导管癌中BRCA 1、APC、p16和TIMP-3基因甲基化率分别为60.3%、58.6%、39.3%和30.9%。在单个导管癌的多个显微切割区域中观察到DNA甲基化状态的相当大的异质性，每个区域的甲基化基因数量与肿瘤分化较差显著相关（P = 0.0249）。导管癌中甲基化基因平均数与DNMT 1蛋白表达水平显著相关（P = 0.0093）。这些数据表明，多个肿瘤相关基因的DNA甲基化的积累参与了胰腺从早期癌前阶段到恶性进展的多阶段癌变，DNMT 1蛋白过表达可能是导致这种异常DNA甲基化的原因。
To evaluate the significance of alterations in DNA methylation during multistage carcinogenesis of the pancreas, tissue samples of 13 peripheral pancreatic duct epithelia showing no remarkable histological changes without inflammatory background (DE), 20 peripheral pancreatic duct epithelia showing no remarkable histological changes with inflammatory background (DEI), 40 pancreatic intraepithelial neoplasias (PanIN) and 147 areas of ductal carcinoma were microdissected from surgically resected specimens from 58 patients and were embedded into agarose beads. The embedded tissue samples were subjected to methylation-specific PCR (MSP) to evaluate the DNA methylation status of the p14, p15, p16, p73, APC, hMLH1, MGMT, BRCA1, GSTPI, TIMP-3, CDH1 and DAPK-1 genes. The prevalence of DNA methylation of at least one of the 12 genes and the average number of methylated genes were significantly higher in both DEI (60% and 0.85 +/- 0.88, P = 0.0151 and P = 0.0224, respectively) and PanIN (67.5% and 0.95 +/- 0.85, P = 0.0014 and P = 0.0028, respectively) than in DE (15.4% and 0.15 +/- 0.38), and were further increased in ductal carcinoma (98.3% and 2.50 +/- 1.35, P < 0.0001 and P < 0.0001, respectively). The BRCA1, APC, p16 and TIMP-3 genes were frequently methylated in ductal carcinoma (60.3, 58.6, 39.3 and 30.9%, respectively). Considerable heterogeneity of DNA methylation status was observed among multiple microdissected areas from individual ductal carcinomas, and the number of methylated genes per area was significantly correlated with poorer tumor differentiation (P = 0.0249). The average number of methylated genes in ductal carcinomas was significantly correlated with DNMT1 protein expression level (P = 0.0093). These data suggest that accumulation of DNA methylation of multiple tumor-related genes is involved in multistage carcinogenesis of the pancreas from early precancerous stages to malignant progression and that DNMT1 protein overexpression may be responsible for this aberrant DNA methylation.