Immunoexpression of transforming growth factor β in desmoplastic ameloblastoma

Abstract

Desmoplastic ameloblastoma (DA) is an unusual subtype of ameloblastoma histologically characterized by the pronounced collagenized stroma. In the present study, the immunolocalization of transforming growth factor beta (TGF-beta), one of the most potent local factors for modulating extracellular matrix formation, was observed in DA in order to study its participation in the stromal desmoplasia. Seven cases of DA, including a "hybrid" lesion, were studied together with ten cases of ordinary follicular and plexiform ameloblastomas as the control. In contrast to ordinary ameloblastomas, marked immunoexpression was observed in all DAs but one. In the "hybrid" lesion, TGF-beta was not expressed in the area of follicular ameloblastoma but in that of DA. These results show that TGF-beta produced by tumor cells of DA plays a part in the desmoplastic matrix formation.

Expression of extracellular matrix proteins in ameloblastomas and adenomatoid odontogenic tumors

“…Takata et al [36] veriWed a high expression of transforming growth factor beta (TGF-) in desmoplastic ameloblastomas. TGF-stimulates various cells, including Wbroblasts, to synthesize ECM, such as collagen, Wbronectin, and proteoglycans [36]. Therefore, TGF-may be important for desmoplastic matrix formation [36].…”

“…TGF-stimulates various cells, including Wbroblasts, to synthesize ECM, such as collagen, Wbronectin, and proteoglycans [36]. Therefore, TGF-may be important for desmoplastic matrix formation [36].…”

Comparação da imunoexpressão de VEGF, TGF-β e MMP-9 em ameloblastoma e tumor odontogênico adenomatóide

“…Takata et al [8] investigated the immunolocalization of TGF-β in desmoplastic ameloblastoma (DA) with the aim to study its role in stromal desmoplasia. In the "hybrid" lesion, TGF-β was not found in follicular ameloblastoma, but it was in DA.…”

“…Transforming growth factor-beta (TGF-β) regulates pivotal cellular processes such as proliferation, differentiation, and apoptosis [7]. The cellular distribution of TGF-β receptors along with their oligomerization mode and complex interaction with different cell surface receptors is a crucial requirement for the initiation of distinct signaling cascades [8]. This protein also inhibits degradation of the extracellular matrix both through an inhibitory action of the production of matrix metalloproteinase, and a stimulatory action that activates enzyme inhibitors [8].…”

“…The cellular distribution of TGF-β receptors along with their oligomerization mode and complex interaction with different cell surface receptors is a crucial requirement for the initiation of distinct signaling cascades [8]. This protein also inhibits degradation of the extracellular matrix both through an inhibitory action of the production of matrix metalloproteinase, and a stimulatory action that activates enzyme inhibitors [8]. Matrix metalloproteinase-9 (MMP-9) is a type IV collagenase that plays an active role not only in promoting tumor cell invasion and metastasis, but also as a marker of the tumor invasive phenotype.…”