Thus, the present research was conducted with the following objectives: (1) to support the diagnostic value of MMP-2 and MMP-9 in breast cancer using a highly sensitive zymographic method; (2) to determine the possible association of activity levels of serum forms of MMP-2 and MMP-9 with the current clinical parameters; and (3) to perform the first univariate analysis including c-erbB-2, a candidate marker of tumour aggressiveness, at present in course of validation. The gene discussed is MMP9; the disease is breast cancer.