Matrix metalloproteinases polymorphism in gastrointestinal cancers. Single nucleotide polymorphism (SNP) for matrix metalloproteinases (MMP) genes in gastrointestinal organs (e.g., esophagus, stomach and intestine) of human has been reported. These SNPs are involved in changing MMPs activities in neoplastic transformation of gastric tissues in cancer patients. In addition to cancerous cells, the secretion of MMPs by fibroblasts, myofibroblasts, lymphocytes, neutrophils, macrophages, dendritic cells and endothelial cells has been documented. Both MMPs and tissue inhibitor of metalloproteinases (TIMPs) are important in regulation of extracellular matrix (ECM) remodeling, inflammatory responses and angiogenesis for cancer invasion and metastasis.