Matrix metalloproteinase family as molecular biomarkers in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most common head and neck malignancies. Affected by the nonspecific symptoms, the OSCC patients are usually diagnosed in the advanced stages. To improve the treatment outcome and survival of OSCC, identification of the reliable biomarkers for early detection and prognosis prediction is necessary. Matrix metalloproteinases (MMPs) function in degradation of ECM, generation of active peptides, and activation of specific growth factors, resulting in forming an environment promoting tumor progression, invasion, and metastasis. MMPs can be applied as potential cancer biomarkers for early detection, risk assessment, prognostic analysis, and evaluation of response to treatment in OSCC. Moreover, the detection of MMPs in blood and saliva is a feasible mean to monitor OSCC in a noninvasive manner. Among all of the MMPs, MMP-9 probably appears to be the most promising biomarker with most of the documented cases. However, an updated meta-analysis is needed to confirm the advantages of MMP-9 over other MMPs in monitoring OSCC. Furthermore, an observation that MMP-11 in combination with Ets-1 or vascular endothelial growth factor (VEGF) leads to more accurate prediction in comparison with MMP-11 alone warrants further studies on the use of combined biomarkers in OSCC management.