MMP9 and colorectal carcinoma: The cell-free supernatants of Lactobacillus sp., Lactobacillus casei, and Lactobacillus rhamnosus GG reduce metalloproteinase 9 (MMP-9) activity and increase the expression of a tight junction protein, zona occludens 1 (ZO-1), thereby inhibiting the invasiveness of colorectal carcinoma cells [31].