Epimutation and cancer: a new carcinogenic mechanism of Lynch syndrome             (Review).
Epimutation is defined as abnormal transcriptional repression of active             genes and/or abnormal activation of usually repressed genes caused by errors in             epigenetic gene repression. Epimutation arises in somatic cells and the germline,             and constitutional epimutation may also occur. Epimutation is the first step of             tumorigenesis and can be a direct cause of carcinogenesis. Cancers associated             with epimutation include Lynch syndrome (hereditary non-polyposis colorectal cancer,             HNPCC), chronic lymphocytic leukemia, breast cancer and ovarian cancer. Epimutation             has been shown for many tumor suppressor genes, including RB, VHL, hMLH1, APC             and BRCA1, in sporadic cancers. Methylation has recently been shown in DNA from             normal tissues and peripheral blood in cases of sporadic colorectal cancer and             many studies show constitutive epimutation in cancers. Epimutation of DNA mismatch             repair (MMR) genes (BRCA1, hMLH1 and hMSH2) involved in development familial cancers             has also been found. These results have led to a focus on epimutation as a novel             oncogenic mechanism.
Department of Obstetrics and Gynecology, School of Medicine, Keio University, Tokyo, Japan. kbanno@z7.keio.jp
Kouji
K
Banno
Iori
I
Kisu
Megumi
M
Yanokura
Kosuke
K
Tsuji
Kenta
K
Masuda
Arisa
A
Ueki
Yusuke
Y
Kobayashi
Wataru
W
Yamagami
Hiroyuki
H
Nomura
Eiichiro
E
Tominaga
Nobuyuki
N
Susumu
Daisuke
D
Aoki
D002471:Cell Transformation, Neoplastic; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000235:genetics*; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000235:genetics*; D044127:Epigenesis, Genetic; D015972:Gene Expression Regulation, Neoplastic; D018095:Germ-Line Mutation; D006801:Humans; D009154:Mutation; D014158:Transcription, Genetic; D015533:Transcriptional Activation
D004273:DNA, Neoplasm