Stromelysin-3 is expressed by aggressive meningiomas.

Abstract

Stromelysin-3 (ST3) that belongs to the metalloproteinase family is proposed to play a role in tumor invasion. The purpose of this work was to study the variation of ST3 expression in meningiomas. Twenty atypical meningiomas were retrieved from the Pathology Department's files at Hopital de Bellevue, Saint-Etienne, France. They were compared with 20 benign meningiomas randomly selected from the same file. The tumors were classified using standard histologic criteria. Frozen sections of the tumors were immunostained for ST3 and MIB-1 to evaluate the proliferative activity of tumor cells. The study included 5 fibrous meningiomas, 10 transitional meningiomas, 20 syncitial meningiomas, 2 secretory meningiomas, 2 microcystic meningiomas, and 1 angiomatous meningioma. Stromelysin-3 was expressed within the stromal and neoplastic cells of only 1 benign meningioma and 13 atypical meningiomas. The MIB-1 proliferation index was significantly higher in the meningiomas expressing ST3 (Student t test: P < 0.001). The invasion of bone, muscle, and brain by meningiomas as well the recurrence were statistically correlated with their ST3 expression (Kruskal-Wallis nonparametric correlation test, P = 0.001 and P = 0.008, respectively). Stromelysin-3 might play an important role in the invasiveness of meningiomas. Therefore, considering, ST3 in association with evaluation of the MIB-1 proliferating index may be an useful tool to assess the behavior of meningiomas.