Mutational analysis of Wnt signaling molecules in ameloblastoma with aberrant nuclear expression of β‐catenin

Abstract

Mutations in CTNNB1, APC, AXIN1, and AXIN2 are not implicated in nuclear accumulation of beta-catenin, and that the expression of cyclin D1 is accelerated independently of beta-catenin in ameloblastomas. Other Wnt signaling members or alternative pathways involved in the degradation of beta-catenin should be subject of further investigation.

A novel ameloblastoma cell line (AM-3) secretes MMP-9 in response to Wnt-3a and induces osteoclastogenesis

“…It was reported that cytoplasmic expression of b-catenin was observed in ameloblastoma tissue 39 and that a genomic mutation of b-catenin could activated b-catenin-dependent canonical Wnt pathways in ameloblastoma. 40 In this study, we examined whether AM-3 cells express Wnt family members. In comparison with normal oral epithelium-derived cells (MOE1b), AM-3 and AM-1 cells had higher expressions of Wnt-5a, Fz-2, and Fz-8 and mildly elevated expressions of other Wnts and Wnt receptors.…”

Immunohistological Features in Adenomatoid Odontogenic Tumor: Review of the Literature and First Expression and Mutational Analysis of β-Catenin in This Unusual Lesion of the Jaws

“…A mutation at codon 40 of the exon 3 of the gene was found in one case of follicular ameloblastoma. Tanahashi et al 11 showed a significant nuclear accumulation of b-catenin in cuboidal cells of regions with a follicular appearance in 18 cases of ameloblastoma. Siriwardena et al 10 conducted a study to clarify the relation of b-catenin accumulation and mutations of CTNNB1 and APC in the process of development of 6 ameloblastomas and 8 odontogenic carcinomas.…”

“…1 Despite these advances for a better characterization of this tumor, the histogenesis of AOT is still under debate. Because the Wnt-signaling pathway is crucial in the formation of human teeth, alterations of the b-catenin gene (CTNNB1) sequence and of its protein product expression have been investigated in some odontogenic tumors [7][8][9][10][11] . However, to our knowledge, the status of bcatenin has not been explored in AOT so far.…”

Molecular markers of cell adhesion in ameloblastomas. An update

“…Various immunohistochemistry analyses of β-catenin in AMs have indicated that β-catenin is expressed in the cytoplasm and cell membrane, as well as in columnar epithelial cells that resemble the stellate reticulum. However, nuclear expression of β-catenin was observed mainly in the SMA variants and in odontogenic carcinomas (10,16,17). This finding is important because the nuclear expression or nuclear accumulation of β-catenin might indicate abnormal Wnt signaling, which could be related to tumorigenesis and cell proliferation in AMs (16-18) (Fig.…”

“…Therefore, the nuclear accumulation of β-catenin might be related to AM variants that exhibit aggressive, invasive and recurrent behaviors and might also be associated with increased cell proliferation (13,16,17). …”