title: Expression of matrix metalloproteinases 2 and 7 in tumor cells correlates with the World Health Organization classification subtype and clinical stage of thymic epithelial tumors.
abstract: To investigate the roles of matrix metalloproteinases (MMPs) in thymic epithelial tumors, we examined the expression of MMP-2, -7, and -9; membrane-type 1 (MT1)-MMP; and tissue inhibitor of metalloproteinase-2 (TIMP-2) in 57 tumors by immunohistochemistry and in selected 15 cases by in situ hybridization. The tumors consisted of 5 type A, 12 type AB, 11 type B1, 11 type B2, 9 type B3, and 9 type C thymomas according to the World Health Organization histologic classification system and of 22 stage I, 13 stage II, 8 stage III, and 14 stage IV thymomas according to the Masaoka staging system. In the positive cases, MMPs and TIMP-2 were expressed in both tumor cells and stromal cells. The cellular localization of MMPs detected by immunohistochemistry was almost identical with that of the mRNA signals detected by in situ hybridization. MMP-2 and MMP-7 were predominantly expressed in type B3 thymoma and type C thymoma, respectively. Expression of MT1-MMP and TIMP-2 correlated with that of MMP-2, indicating a proteolytic activation of the latter. MMP-9 was prominent in type B2 thymoma. Expression in tumor cells of MMP-2 or MMP-7 was also correlated with clinical stage. The present study suggests that certain MMPs may play an important role in the tumor progression of different subtypes of thymic epithelial tumors and that MMP-2 and MMP-7 may contribute to the tumor aggressiveness and malignant potential.
authors.affiliation: Department of Pathology, Nagoya City University Medical School, Aichi, Japan.
authors.forename: Emiko
authors.initials: E
authors.lastname: Takahashi
authors.forename: Hisashi
authors.initials: H
authors.lastname: Tateyama
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Akatsu
authors.forename: Ichiro
authors.initials: I
authors.lastname: Fukai
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Yamakawa
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Fujii
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Eimoto
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis*; D020783:Matrix Metalloproteinase 7 / Q000096:biosynthesis*; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000096:biosynthesis; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D013953:Thymus Neoplasms / Q000145:classification* / Q000201:enzymology / Q000473:pathology*; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000096:biosynthesis; D014944:World Health Organization
chemical_list: D019716:Tissue Inhibitor of Metalloproteinase-2; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases; D020783:Matrix Metalloproteinase 7; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9