MMP9 and lung cancer: By contrast, there was no difference in the frequency of the AG/GG allele of MMP-13-77A/G (p > 0.05).The results demonstrated a significant association between CT genotype and the T allele and a decreased risk of lung cancer in MMP9-1562C/T (p = 0.001, OR = 0.45, 95% CI = 0.29–68) compared with the CT+TT genotype; the C allele was associated with increased risk of developing lung cancer (p = 0.00, OR = 2.0, 95% CI =1.36–2.95) compared with that of the T allele in case–control research.