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Heterogeneous microsatellite instability observed within epithelium of ulcerative colitis
Author(s) -
Ozaki Kazuhide,
Nagasaka Takeshi,
Notohara Kenji,
Kambara Takeshi,
Takeda Masanori,
Sasamoto Hiromi,
Jass Jeremy R.,
Tanaka Noriaki,
Matsubara Nagahide
Publication year - 2006
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.22095
Subject(s) - microsatellite instability , msh2 , dna mismatch repair , mlh1 , ulcerative colitis , msh6 , colorectal cancer , dysplasia , pathology , microdissection , cancer , biology , cancer research , laser capture microdissection , carcinogenesis , microsatellite , medicine , gene , gene expression , genetics , allele , disease
Microsatellite instability (MSI) has been associated with colitic cancer. However, reported frequency of MSI was varied and the association of MSI with mismatch repair (MMR) deficiency was unclear. In addition, the occurrence of genetic alterations in stromal cells within ulcerative colitis (UC) is still controversial. We therefore sampled 164 microareas in various pathological lesions of UC with or without colitic cancer and studied the MSI status in relation to the DNA repair protein expressions. A total of 129 microfoci from colorectal tissue of 5 colitic cancer patients and 35 microfoci of 7 UC patients (without neoplasm) were carefully sampled by laser‐capture microdissection. MSI was analyzed in each microsamples. The protein expression of MMR genes ( MLH1 , MSH2 , MSH6 ), O 6 ‐methylguanine‐DNA methyltransferase and p53 were assessed by immunohistochemical analysis. Variety of di‐nulcleotide microsatellite markers was altered in individual microfoci from different morphological epithelial lesions, in full range of nonneoplastic epithelium to colitic cancer. Interestingly, MSI was not observed in stromal cells at any sites, including those within colitic cancer/dysplasia lesions. Expression of the MMR proteins was not lost in any of the lesions examined. Microsatellite alterations rather seem to be related to the initiation than to the progression of colitic cancer. © 2006 Wiley‐Liss, Inc.