The Sp1 binding site is essential for basal transcriptional activity of both MMPs as only ∼10% and ∼30% of transcription activity is observed when Sp1 at −102 on MT1-MMP in human fibrosarcoma HT-1080 and at −91 on MMP-2 in astroglioma cells is mutated respectively [38], [39]. Here, SP1 is linked to astrocytic tumor.