title: NAD(P)H:quinone oxidoreductase-dependent risk for colorectal cancer and its association with the presence of K-ras mutations in tumors.
abstract: NAD(P)H:quinone oxidoreductase (NQO1) is a polymorphic enzyme involved in the detoxification of potentially mutagenic and carcinogenic quinones. The homozygous C609T NQO1 genotype resulting in loss of reductase activity is found in 2-20% of individuals. In the present study, the NQO1-dependent risk for sporadic colorectal cancer (CRC) was studied in 247 incident CRC cases and 296 hospital-based controls recruited during 1996-1997. Four subgroups of cases were studied: (i) all CRCs; (ii) a molecular CRC subgroup (n = 117, cases with molecular tumor analyses); (iii) within the molecular subgroup those tumors with K-ras mutations in codon 12 (CRC K12); (iv) within the molecular subgroup those tumors with K-ras mutations in codon 13 (CRC K13). The C609T NQO1 genotype was found to be twice as prevalent in all CRC patients (6.8%) compared with controls (3%) and six times more common in the subset CRC K12 (20%). Multivariant analyses in the overall population of 247 cases and 296 controls showed a significant age and gender adjusted risk for CRC associated with the C609T NQO1 genotype (OR 2.9, 95% CI 1.19-6.97; P = 0.01) or with any variant genotype (the low activity allele frequency, i.e. heterozygotes plus homozygotes) (OR 1.41, 95% CI 1.02-1.92; P = 0.03). Within cases of the molecular subgroup (n = 117) the C609T NQO1 genotype was associated with the presence of K-ras codon 12 mutation (OR 6.5 95%, CI 1.39-34.9; P = 0.003). Logistic regression showed an age and gender adjusted risk for K-ras codon 12 mutant CRC associated with the C609T NQO1 genotype (OR 10.5, 95% CI 2.99-36.7; P: = 0.0002) or with any variant NQO1 genotype (OR 2.23, 95% CI 1.23-4.00; P = 0.007) compared with the control group. Genetically determined variations in NQO1 may modify the risk for CRC and these risks may be greatest for tumors containing K-ras codon 12 mutations. CRC with K-ras codon 12 mutations may represent a distinct and etiologically more homogeneous subtype of the disease, which may be associated with toxicants that are metabolized via a NQO1-dependent pathway.
authors.affiliation: Department of Surgery, Hospital Clinic, Department of Pharmacology, School of Medicine, Casanova 143, E-08036, Barcelona, Spain. alafuente@med.ub.es
authors.forename: M J
authors.initials: MJ
authors.lastname: Lafuente
authors.forename: X
authors.initials: X
authors.lastname: Casterad
authors.forename: M
authors.initials: M
authors.lastname: Trias
authors.forename: C
authors.initials: C
authors.lastname: Ascaso
authors.forename: R
authors.initials: R
authors.lastname: Molina
authors.forename: A
authors.initials: A
authors.lastname: Ballesta
authors.forename: S
authors.initials: S
authors.lastname: Zheng
authors.forename: J K
authors.initials: JK
authors.lastname: Wiencke
authors.forename: A
authors.initials: A
authors.lastname: Lafuente
mesh_terms: D000367:Age Factors; D000368:Aged; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D005260:Female; D011905:Genes, ras / Q000235:genetics*; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009154:Mutation; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000235:genetics* / Q000378:metabolism; D009367:Neoplasm Staging; D011110:Polymorphism, Genetic; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking; D012959:Socioeconomic Factors
chemical_list: D016660:NAD(P)H Dehydrogenase (Quinone)