Exposure to aluminum also altered the expression and secretion of various proteins associated with angiogenesis, tumorigenesis, and metastasis, including E-cadherin, vimentin, Snail, transforming growth factor-β, matrix metalloproteinases 7 and 9, and vascular endothelial growth factor.13 That study demonstrated that gastrointestinal tract exposure to aluminum may be a risk factor for the initiation of metastasis in colorectal cancer cells. This evidence concerns the gene MMP7 and colorectal cancer.