Among the various members of the MMP family, MMP-9, MMP-2 or MT1-MMP are especially involved in the development or progression of uterine cervical tumors, as indicated by the finding that their RNA or protein expression and their activity are extremely low or absent in normal uterine cervix and low-grade CIN, are well detectable in high-grade CIN and they are very high in invasive CC [100,101,102,103,104,105,106,107,108,109,110,111,112]. This evidence concerns the gene MMP9 and cervical squamous intraepithelial neoplasia.