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Incidence of −93 MLH 1 promoter polymorphism in familial and sporadic colorectal cancer
Author(s) -
MartínezUrueña N.,
Macías L.,
PérezCabornero L.,
Infante M.,
Lastra E.,
Cruz J. J.,
Miner C.,
González R.,
Durán M.
Publication year - 2013
Publication title -
colorectal disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.029
H-Index - 89
eISSN - 1463-1318
pISSN - 1462-8910
DOI - 10.1111/codi.12112
Subject(s) - colorectal cancer , genotype , microsatellite instability , medicine , immunohistochemistry , gastroenterology , incidence (geometry) , cancer , single nucleotide polymorphism , allele , biology , microsatellite , genetics , gene , physics , optics
Abstract Aim The MLH 1 promoter contains a common single nucleotide polymorphism (−93 guanine > adenine) located in an essential region for maximum transcriptional activity. This has been associated with an increased risk of microsatellite instability ( MSI ) colorectal cancer. The aim of the study was to compare the distribution of MLH 1 −93G>A genotypes between patients with familial colon cancer, sporadic colon cancer and healthy subjects. Method We genotyped 200 familial colon samples, 183 cases of sporadic colon cancer and 236 control subjects. MSI was analysed. Results The GA genotype was under‐represented in patients with familial colon cancer, whereas the AA genotype was over‐represented in cases of sporadic colon cancer. A greater frequency of the MLH 1 GA genotype was found in the cancer cases with MLH 1 focal immunohistochemistry ( IHC ) for anti‐ MLH 1 antibody. When we compared genotype distribution in the familial colorectal cancer cases with and without MSI , we failed to detect any correlation, although the GA genotype is more frequent in cases with MSI . Conclusion There is a relationship between the MLH 1 −93G>A polymorphism in the homozygous state and the risk of sporadic colorectal cancer. The variant MLH 1 −93G>A appears to be related to cases with focal IHC activity more than to complete absence of the MLH 1 protein in the tumour tissue.