Multiple MMP subspecies including MMP-2, MMP-9, MMP-13 and MMP-14, can cut specific GPLGVRGC sequences, which have been widely applied for cancer stimulation therapy.36 Besides this, the PG-6 peptide (PLGALG)37 is another MMP discriminating peptide that can be identified and cut by the MMP-2 and MMP-9 subspecies. The gene discussed is MMP9; the disease is cancer.