With this design, the MMP-9 levels in cancer and normal cells, as well as in various metastasis stages, were evaluated, revealing that the cellular MMP-9 in cancer cells display a higher content than normal cells, and the levels in high malignant SW620 and MDA-MB-231 cells are higher than those in low malignant MCF-7 and HeLa cells. The gene discussed is MMP9; the disease is cancer.