title: Single nucleotide polymorphisms in the EXO1 gene and risk of colorectal cancer in a Japanese population.
abstract: EXO1 is a member of the RAD2 nuclease family and functions in DNA replication, repair and recombination. We investigated the relationship of single nucleotide polymorphisms (SNPs) at exon 10 (T439M) and exon 13 (P757L) of the EXO1 gene with development, progression and metastasis of colorectal cancer. For T439M, the Thr/Met genotype [odds ratio (OR) = 2.03, 95% confidence interval (CI) 1.04-3.98] and Thr/Met and Met/Met genotypes combined (OR = 2.37, 95% CI 1.23-4.56) demonstrated significant association with the development of colorectal cancer after adjusting for age, gender and smoking status. For P757L, patients with the Leu/Leu genotype showed a reduced risk of colorectal cancer (adjusted OR = 0.398, 95% CI 0.183-0.866) when the Pro/Leu and Pro/Pro genotypes were combined and used as the reference. The Leu/Leu genotype also had a reduced risk (adjusted OR = 0.373, 95% CI 0.164-0.850) when the Pro/Leu genotype was used as the reference. Individuals who carried both putative risk genotypes (Thr/Met and Met/Met for T439M and Pro/Leu for P757L) showed an adjusted OR of 4.95 (95% CI 1.56-15.7) compared with those who carried both low risk genotypes. Analysis of microsatellite instability (MSI) revealed that tumors from individuals who carried both putative risk genotypes tended to have a higher frequency of MSI positives than those from patients who carried both low risk genotypes, although a significant correlation was not found between EXO1 genotype and MSI status. This is the first report to provide evidence for an association of EXO1 gene polymorphisms with colorectal cancer risk. The EXO1 genotypes were not associated with any clinicopathological characteristics in colorectal cancer patients.
authors.affiliation: Department of Cancer and Thoracic Surgery, Graduate School of Medicine and Dentistry, Okayama University, 2-5-1 Shikata-cho, Okayama 700-8558, Japan.
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Hiroko
authors.initials: H
authors.lastname: Hanafusa
authors.forename: Mamoru
authors.initials: M
authors.lastname: Ouchida
authors.forename: Masaaki
authors.initials: M
authors.lastname: Yano
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Suzuki
authors.forename: Masakazu
authors.initials: M
authors.lastname: Murakami
authors.forename: Motoi
authors.initials: M
authors.lastname: Aoe
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Shimizu
authors.forename: Kei
authors.initials: K
authors.lastname: Nakachi
authors.forename: Kenji
authors.initials: K
authors.lastname: Shimizu
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000235:genetics*; D045643:DNA Repair Enzymes; D005090:Exodeoxyribonucleases / Q000235:genetics*; D005091:Exons / Q000235:genetics; D005260:Female; D020022:Genetic Predisposition to Disease; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D007564:Japan; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics*; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012907:Smoking / Q000009:adverse effects
chemical_list: C114331:EXO1 protein, human; D005090:Exodeoxyribonucleases; C028450:exodeoxyribonuclease I; D045643:DNA Repair Enzymes