The expression of MMP-2 and Ki-67 in head and neck melanoma, and their correlation with clinic-pathologic indices

Objective: Melanoma is an aggressive tumor with propensity for early metastasis and poor prognosis with delayed diagnosis. Matrix metalloproteinase-2 (MMP-2) is involved in degradation of extra-cellular matrix proteins and tumor progression. Ki-67 is a predictor of tumor proliferation activity but its prognostic significance in melanoma is controversial. In this study, the prognostic value of MMP-2 and Ki-67 via immuno-staining in head and neck melanoma is investigated. Material and Methods: A retrospective analysis of 24 consecutive primary melanoma samples was performed. All samples were stained with monoclonal MMP-2 and Ki-67 antibodies. Two independent investigators evaluated the stained sections. The reactive cells were considered positive regardless of the staining intensity and reported as percentage. Results: A strong correlation between MMP-2 expression, Breslow tumor thickness, and Clark level of invasion was observed (r = 0.85, P < 0.0001 and r = 0.84, P < 0.0001, respectively). A significant positive correlation was observed between MMP-2 expression and number of lymph node involved (r = 0.55, P value 0.005). MMP-2 over expression (> 50%) was an independent predictor of lymph node involvement (OR: 2.1, P value: 0.01). No significant association was observed between Ki-67 expression and Breslow tumor thickness, Clark level, or lymph node involvement. Conclusion: MMP-2 expression correlates with tumor thickness in melanoma and is an independent predictive factor for lymph node involvement.