Oral and Extraoral Intermediate Tumors: Are MMP-9 and Ki-67 Biomarkers Correlated to Their High Recurrence Rates?

Intermediate tumors of the head and neck fall in the borderline category. They are clinically aggressive tumors with no malignant phenotyping. They are locally infiltrative and have high recurrence rate with less chances to metastasize. The standard care is surgical excision with wide margins. However, surgeons are challenged with the anatomic complexity of the head and neck, increasing the susceptibly of satellite cells being left behind. Ki-67 and MMP-9 are proliferative index and extracellular matrix degradation biomarkers, respectively. They are directly correlated to malignant tumors, whereas less associated with the benign ones. Our main objective was to correlate between Ki-67 and MMP-9 expressions and the recurrence rates in these borderline tumors. We performed a retrospective immunohistochemical study comparing the immunoexpression of Ki-67 and MMP-9. Tumors of interest were aggressive fibromatosis (AF, n=70), epithelioid hemangioendothelioma (EHE, n=25), hemangiopericytoma (HP, n=25), benign fibrous histiocytoma (BFH, n=80) and juvenile ossifying fibroma (JOF, n= 40). Our results revealed that AF followed by HP showed significant high levels of MMP-9 expression, with an average positive area percentage of 40% and 37.4% respectively, compared with other tumors (P<0.05). Ki-67 immunoreaction was significantly the lowest in AF (2.3%, P<0.05) and the highest in JOF (24.7%). To conclude, MMP-9 can be used as a possible target in these tumors as an adjuvant therapy to minimize recurrence rates.