Expression of MMP-10, MMP-21, MMP-26, and MMP-28 in Merkel cell carcinoma

Merkel cell carcinoma (MCC) is an aggressive cutaneous tumor with poor outcome and increasing incidence. We examined by immunohistochemistry the expression of three novel matrix metalloproteinases (MMPs)—MMP-21, MMP-26, and MMP-28—in 44 primary MCC tumors and six lymph node metastases while MMP-10 served as a positive control. Their mRNA expression was also studied in the UISO MCC cell line basally and after various stimulations using quantitative real-time PCR. MMP-28 was observed in tumor cells of 15/44 samples especially in tumors