Association Between -1562C/T Polymorphisms in the Matrix Metalloproteinase-9 and the Risk of Lung Cancer Among South-Central Chinese Population

Matrix metalloproteinase (MMP) is a group of highly conserved metal-dependent protolytic enzymes. The main function of matrix metalloproteinases-9 (MMP-9) is to breakdown extracellular matrix, which is associated with the susceptibility to different cancers. The purpose of this study was to investigate the association between the gene polymorphism -1562C/T of MMP-9 and lung cancer risk among South-Central Chinese population. The polymerase chain reaction-restriction fragment length polymorphism analysis and sequencing were used to detect the gene polymorphism -1562C/T of MMP-9 in 182 pathologically diagnosed patients with lung cancer and 169 controls. The genotype frequencies of MMP-9 polymorphism were 82.4% (CC), 17.6% (CT), 0% (TT) in cases and 66.3% (CC), 33.7% (CT), 0% (TT) in controls. Compared with the T allele, the C allele was significantly associated with an increased risk for the lung cancer patients (OR = 2.105, 95% CI = 1.327–3.338, P = 0.001). The frequencies of T allele in cases and controls were 8.8% and 16.9% respectively, which was the minor allele frequency with higher prevalence in controls than in lung cancer patients. The distribution of the MMP-9 genotypes in cases and controls was in accordance with Hardy-Weinberg equilibrium. These findings suggested that the MMP-9 -1562CC genotype might be a marker of increased genotype susceptibility to lung cancer among South-Central Chinese population.