title: A functional variant (-1304T>G) in the MKK4 promoter contributes to a decreased risk of lung cancer by increasing the promoter activity.
abstract: Mitogen-activated protein kinase kinase 4 (MKK4) is a critical mediator of stress-activated protein kinase signals that regulate apoptosis, inflammations and tumorigenesis. Several polymorphisms have been identified in the MKK4 gene. We hypothesized that genetic variants in the MKK4 promoter may alter its expression and thus cancer risk. In a case-control study of 1056 lung cancer cases and 1056 sex and age frequency-matched cancer-free controls, we genotyped two common polymorphisms in the MKK4 promoter region (-1304T>G and -1044A>T) with the Taqman assay, and we found that compared with the most common -1304TT genotype, carriers of -1304G variant genotypes had a decreased risk of lung cancer [odds ratio (OR) = 0.74; 95% confidence interval (CI) = 0.61-0.90 for TG, and OR = 0.62; 95% CI = 0.41-0.94 for GG] in an allele dose-response manner (adjusted P(trend) = 0.0005). Further stratification analysis showed that the protective role of the -1304G variant allele was more evident in low or normal body mass index (BMI) but restrained in the overweighters and that the -1304G variant genotypes interacted with BMI in reducing cancer risk (adjusted P(interaction) = 0.003). Moreover, the luciferase assay showed that the G allele in the promoter significantly increased the transcription activity of the MKK4 gene in vitro and that the MKK4 protein expression levels of the G variant carriers was significantly higher in tumor tissues than those of the -1304TT genotype. However, no significant association was observed between the -1044A>T polymorphism and risk of lung cancer. Our data suggest that the functional -1304G variant in the MKK4 promoter contributes to a decreased risk of lung cancer by increasing the promoter activity and that the G variant may be a marker for susceptibility to lung cancer.
authors.affiliation: The Institute for Chemical Carcinogenesis, Guangzhou Medical College, People's Republic of China.
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.forename: Dianke
authors.initials: D
authors.lastname: Chen
authors.forename: Lei
authors.initials: L
authors.lastname: Yang
authors.forename: Yinyan
authors.initials: Y
authors.lastname: Li
authors.forename: Xiaoxuan
authors.initials: X
authors.lastname: Ling
authors.forename: Lin
authors.initials: L
authors.lastname: Liu
authors.forename: Weidong
authors.initials: W
authors.lastname: Ji
authors.forename: Yisheng
authors.initials: Y
authors.lastname: Wei
authors.forename: Jianping
authors.initials: J
authors.lastname: Wang
authors.forename: Qingyi
authors.initials: Q
authors.lastname: Wei
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Jiachun
authors.initials: J
authors.lastname: Lu
mesh_terms: D000368:Aged; D002353:Carrier State; D045744:Cell Line, Tumor; D005260:Female; D017930:Genes, Reporter; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D015810:Linkage Disequilibrium; D008156:Luciferases / Q000235:genetics; D008175:Lung Neoplasms / Q000453:epidemiology / Q000235:genetics*; D048670:MAP Kinase Kinase 4 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D010957:Plasmids; D011110:Polymorphism, Genetic; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012016:Reference Values; D012307:Risk Factors; D014162:Transfection
chemical_list: D008156:Luciferases; D048670:MAP Kinase Kinase 4; C482559:MAP2K4 protein, human