Recently, in the field of anti-cancer therapeutics, recombinant L. lactis NZ9000 was used to secrete tumour metastasis-inhibiting peptides such as KiSS1 which inhibited HT-29 cell proliferation and migration through the induction of apoptosis pathways and by down regulating matrix metallopeptidase 9 (MMP-9) expression. This evidence concerns the gene MMP9 and cancer.