Japanese
English
- 有料閲覧
- Abstract 文献概要
- 1ページ目 Look Inside
- 参考文献 Reference
- サイト内被引用 Cited by
要旨 大腸癌の発癌機序は,発生部位によって異なっていることが指摘されている.筆者らは,癌および周囲粘膜から採取された分離腺管の分子異常を発生部位別に検討した.203例(左側133例,右側70例)の癌および80例の背景粘膜から腺管分離法で分離腺管を回収した.癌腺管のDNAを用いて,p53,K-ras,BRAF変異,LOH〔loss of heterozygosity(1p,5q,17p,18q,22q)〕およびMSI(microsatellite instability)解析を行った.さらに,癌腺管および正常腺管のDNAメチル化解析(SFRP1,SFRP2,SFRP5,DKK2,DKK3,mir34b/c,RASSF1A,IGFBP7,p16,MLH1)も検討した.癌腺管で,p53変異は左側に多く,BRAF変異は右側に多かった.各染色体のLOHおよびmir34b/cのメチル化の頻度は左側で高く,一方,DKK3,RASSF1A,MLH1のメチル化頻度は右側で高かった.背景粘膜の正常腺管のメチル化率はSFRP1,SFRP2で比較的高く,背景の正常腺管では一定の遺伝子でメチル化率の上昇がみられた.大腸癌発癌メカニズムは左側と右側では異なることが示唆された.
Previous study has suggested that the molecular mechanism differs depending on the site of occurrence(left-sided or right-sided of colorectum)in colorectal cancers. We examined molecular abnormality in cancer and its surrounding mucosa for each site of occurrence using the crypt isolation method. Isolated glands were collected from cancer(203cases)and its background mucosa(80cases)in colorectal cancers(left side : 133cases, right side : 70cases). We examined mutations(p53, K-ras, BRAF), LOH(loss of heterozygosity, 1p, 5q, 17p, 18q, 22q)and methylations(SFRP1, SFRP2, SFRP5, DKK2, DKK3, mir34b/c, RASSF1A, IGFBP7, p16, MLH1). In tumor glands, p53 mutation was observed predominantly on the left-sided cancers whereas mutation of BRAF was observed on the right-sided cancers. In addition, LOH-high status was significantly higher in left-sided cancers than in right-sided cancers, On the other hand, methylation frequencies of DKK3, RASSF1A and MLH1 were higher on the right-sided cancers. Methylation-high status was more frequently found in right-sided cancers compared with left-sided cancers. MSI-positive status was preferentially found in right-sided cancers. Methylation of normal gland on background mucosa was relatively higher in SFRP1 and SFRP2. Our data confirm that distinct molecular pathways to colorectal cancer dominate in the left and right sides of the bowel. An increase in methylation rate was observed for certain genes in normal glands.
Copyright © 2012, Igaku-Shoin Ltd. All rights reserved.