Localization of Oxytalan Fiber, type III Collagen and BMP Family in Conventional and Desmoplastic Ameloblastoma

Abstract

Abstract:The histologic hallmark distinguishing desmoplastic ameloblastoma (DA) from conventional ameloblastoma (CA) is its pronounced stromal desmoplasia, and this formed the basis of this investigation. To elucidate the stromal characteristics, localization patterns of oxytalan fibers, type III collagen and BMP family in DA (n=8) was compared with CA (n=24), and periodontal ligament (PL) (n= 8). Oxytalan fibers formed apico-occlusal bundles in PL, thick radial bundles around tumor nests in DA, and as scanty fibers in CA. Type III collagen was identified in PL, strongly expressed in DA stroma, but weakly in CA. BMP-2, -3, -4 and -7 expression patterns in tumor epithelium and stroma were more pronounced in DA (including sites of bone formation), than CA. No immunoreactivity for BMP-5 and -6 were detected. Current findings suggest that the stroma in DA is neoplastic and derived from odontogenic ectomesenchyme, and recommends its reclassification as an odontogenic epithelial-ectomesenchymal neoplasm.

Co-expression of BMP-2 and -7 in the Tumoral Epithelium of CEOT with Selective BMP-7 Expression in Amyloid Materials

“…In contrast, another study observed that BMP-2, -4 and -7 were identified in all ameloblastoma subsets with BMP-7overexpression in the acanthomatous variant 13) . These findings were further supported by a recent study that further demonstrated presence of these BMPs as well as BMP-3 in the tumoral and nontumoral component of ameloblastoma with upregulation of BMP-2, -3, -4 and -7 in the desmoplastic variant 14) .…”

“…This study also revealed that the expression patterns of BMPs in the CEOT are distinctive from other odontogenic epithelial neoplasm such as the ameloblastoma 14) . We speculated that these differences might be related to different functional activities of the BMP signaling molecules during the oncogenesis and cytodifferentiation of these tumor entities.…”

“…It is known that BMPs especially BMP-2, -4 and -7 are involved in modulating epithelial-mesenchymal interactions during tooth development [9][10][11] . However reports of aberrant BMP activity in neoplastic odontogenic tissues remain conflicting [12][13][14] .…”

“…Odontogenic tumors constitute a clinically significant group of jawbone neoplasms in the Asian region and are therefore a subject of considerable research [14][15][16][17][18][19][20][21][22][23][24][25] . Among the most well-studied are ameloblastomas [14][15][16][17][18][19] , adenomatoid odontogenic tumor 15,20) , keratocystic odontogenic tumor [21][22][23] and calcifying cystic odontogenic tumor [24][25] . These works have enumerated the clinicopathologic characteristics and clarified the various signaling molecules implicated in the development of the various tumor entities [15][16][17][18][19][20][21][22][23][24][25] .…”

Immunohistochemical Characteristics of Odontogenic Neoplasms and Their Physiological Counterparts

“…Some variants have been sub-classified as follows: solid/multicystic, extraosseous/peripheral, desmoplastic, and unicystic 10,22,24) .…”