Actually, increased expression of MMP‐9 has been documented in many different histological types of human malignant tumours and their metastasis, such as oral, larynx, gastric, lung, liver, breast, bone, skin and cervical.11, 13, 14, 15, 16, 17, 18, 19 Therefore, MMP‐9 and its family members, such as MMP‐2, are considered as the prognostic biomarkers for various carcinomas. This evidence concerns the gene MMP9 and cancer.