Active and inactive forms of matrix metalloproteinases 2 and 9 in cutaneous melanoma

Cutaneous melanoma is the most aggressive type of skin cancer, with high implications on the morbidity and mortality of patients. Matrix metalloproteinases (MMP) 2 and 9 have been involved in melanoma progression because they degrade important components of the basement membrane. We studied the relationship between the levels of active and inactive MMP 2, MMP 9, and clinicopathological parameters.

Expression of both active and latent forms of MMP 2 and MMP 9 was evaluated by zymography in 21 melanoma tissue samples and 19 benign melanocytic nevi samples.

In the melanoma group, inactive MMP 2 was detected in 100% of samples and active MMP 2 in 95%. Inactive MMP 9 was detected in 85% of samples and active MMP 9 in 38%. In the nevi group, 78.9% of samples expressed inactive MMP 2, 5.26% active MMP 2, 21% inactive MMP 9, and 0% active MMP 9. Both forms of MMP 2 and MMP 9 were found to be correlated with skin tumor malignancy. Expression of active and latent MMP 9 was higher in tumors >2 mm thick (P = 0.03, P = 0.014). A correlation was also found between positive lymph node metastasis, inactive MMP 9, and active MMP 9 expression (r = 0.59 P < 0.01, r = 0.668, P < 0.01). The amount of active and latent form of MMP 2 did not have an impact on lymph node metastasis.

Our study demonstrates that active and latent MMP 2 and MMP 9 correlate with melanoma, and both forms of MMP 9 correlate with positive lymph node metastasis.