It is expected that more patient samples and gene profiling datas will help in validation of various prognostic factors i.e. EGFR-1, cell cycle molecules, apoptosis related proteins, VEGF, sVEGFR, matrix metalloproteinase (MMP)-2 and MMP-9, tissue inhibitors of metalloproteinases, plasminogen activators and inhibitors, etc. that are currently in investigation for primary and advanced breast cancer. Here, MMP9 is linked to breast cancer.