Echoing this general patterns, a gel zymography assay with gelatin as substrate showed unaltered secretion of MMP-2 by cell lines AT3 (murine mammary tumor) or MDA-MB-231 (human breast cancer) incubated with F. nucleatum ATCC 23726 or with F. nucleatum ATCC 25586; by contrast, the secretion of MMP-9 was significantly and invariably increased when both cell lines where incubated with each of the two F. nucleatum strains (Fig. 6c). The gene discussed is MMP2; the disease is breast cancer.