Immunohistochemical and Biochemical Evidence of Ameloblastic Origin of Amyloid-Producing Odontogenic Tumors in Cats

Abstract

Amyloid-producing odontogenic tumors (APOT) are rare, and in cats, the histogenesis of the amyloid remains undetermined. In the present study, APOTs in 3 cats were characterized by immunohistochemistry, and the amyloid components analyzed using tandem mass spectrometry. Antiameloblastin antibodies labeled both neoplastic epithelial cells and amyloid in all cases. Neoplastic epithelial cells had strong, diffuse immunoreactivity to antibodies against cytokeratin AE1/AE3, cytokeratin 14, and cytokeratin 19 in all cases and focal immunoreactivity to nerve growth factor receptor antibodies in 2 of 3 cases. Amyloid and some tumor stromal cells were weakly positive for laminin. Calretinin, amelogenin, S100, and glial fibrillary acidic protein antibodies did not label neoplastic epithelial cells or amyloid. Extracted amyloid peptide sequences were compared to the porcine database because the cat genome is not yet complete. Based on this comparison, 1 identical ameloblastin peptide was detected in each tumor. These results suggest that feline APOTs and the amyloid they produce are of ameloblastic lineage.

Amyloid-Producing Odontogenic Tumors of the Facial Skin in Three Cats

“…On the other hand, laminin, vimentin, and odontogenic ameloblastassociated protein (ODAM) have been examined using antibodies specific to these proteins, but positive immunostaining was restricted to a few cats. 1,2,9 Positive labeling of CKs, nerve growth factor receptor, and collagen type I, III and IV have not been detected in the amyloid deposits. 2,9 Therefore, these proteins are not considered to be precursors of amyloid materials, at least in feline APOTs.…”

“…1,2,9 Positive labeling of CKs, nerve growth factor receptor, and collagen type I, III and IV have not been detected in the amyloid deposits. 2,9 Therefore, these proteins are not considered to be precursors of amyloid materials, at least in feline APOTs. 1,2,9 Immunohistochemical characterization of the neoplastic epithelial cells of feline APOTs has been performed in a few studies.…”

“…5 The neoplastic epithelial cells and intratumoral amyloid are considered to be of ameloblastic lineage in canine and feline APOTs. 2,5 To the best of our knowledge, there have been no reports of APOTs occurring on the facial skin of any animals. This report describes the histologic and immunohistochemical features of APOT occurring in the supraorbital and labial dermis of 3 cats.…”

“…2,9 Therefore, these proteins are not considered to be precursors of amyloid materials, at least in feline APOTs. 1,2,9 Immunohistochemical characterization of the neoplastic epithelial cells of feline APOTs has been performed in a few studies. 1,2,9 Positive signals of pan-CK, AE1/AE3, CK14, and CK19 were always detected in the cytoplasm with variable intensity.…”

“…1,2,9 Immunohistochemical characterization of the neoplastic epithelial cells of feline APOTs has been performed in a few studies. 1,2,9 Positive signals of pan-CK, AE1/AE3, CK14, and CK19 were always detected in the cytoplasm with variable intensity. 1,2,9 However, vimentin, laminin, GFAP, S100, calretinin, and ODAM were not detected in all feline APOTs.…”