Overexpression of A disintegrin and metalloproteinase 28 is correlated with high histologic grade in conventional chondrosarcoma

Summary Low-grade chondrosarcoma and enchondroma are occasionally difficult to differentiate solely by reference to clinicoradiologic and histologic findings. The A disintegrin and metalloproteinases are a new gene family of proteins having a metalloprotease domain with matrix metalloproteinases and play an important role in the chondrocyte development process. Therefore, we analyzed the expression of A disintegrin and metalloproteinases and matrix metalloproteinases in several kinds of cartilaginous bone tumors at the messenger RNA level and immunohistochemical protein level and ascertained their relationships to the histologic degree of malignancy. Reverse transciptase-polymerase chain reaction and real-time quantitative reverse transciptase-polymerase chain reaction of the expression of the A disintegrin and metalloproteinase family in cartilaginous bone tumors demonstrated that A disintegrin and metalloproteinase 28 messenger RNA levels in grade I chondrosarcoma were significantly higher than those in enchondroma ( P = .009). Moreover, positive immunoreactivity of A disintegrin and metalloproteinase 28 was observed in 12 (59%) of 22 patients with grade I chondrosarcoma and in 21 (91%) of 23 patients with grade II chondrosarcoma, respectively. In contrast, only 2 (9%) of 21 cases of enchondromas demonstrated positive staining for A disintegrin and metalloproteinase 28. On the other hand, the immunohistochemical expressions of matrix metalloproteinase 9 and matrix metalloproteinase 13 were significantly higher in enchondromas than in normal cartilage tissue; however, there is no statistically different expression between enchondromas and grade I chondrosarcomas. We detected that overexpression of A disintegrin and metalloproteinase 28 was increased according to its histologic grade in conventional chondrosarcoma and could be one of the helpful tools in distinguishing between low-grade chondrosarcoma and enchondroma.