In an another study, Li et al genotyped MMP-12 -82G allele and MMP-13 -77A/G and suggested that these functional polymorphisms might play roles in developing gastric cardia adenocarcinoma (GCA) and esophageal squamous cell carcinoma (ESCC) in high incidence region of North China [19]. This evidence concerns the gene MMP12 and esophageal squamous cell carcinoma.