In a recent study, cell-free supernatants (CFS) from two LAB strains, L. casei and L. rhamnosus GG, were shown to inhibit colon cancer cell invasion by influencing matrix metalloproteinase-9 (MMP-9) activity and levels of the tight junction protein zona occludens-1 (ZO-1) in cultured metastatic human colorectal carcinoma cells [54]. Here, MMP9 is linked to malignant colon neoplasm.