Wu et al investigated that the association of the MMP-9 polymorphisms and their haplotypes with the risk of esophageal SCC (ESCC) and significant differences were found in the genotype and allele distribution of P574R polymorphism of the MMP-9 gene as compared with the CC genotypes among cases and controls (OR = 4.08: 95% CI: 1.58-10.52: p = 0.00). The gene discussed is MMP9; the disease is esophageal squamous cell carcinoma.