Expression of CD56 in Human Tooth Germ, Adenomatoid Odontogenic Tumor, and Ameloblastic Fibroma

Abstract

Background: Odontogenesis is a multistage process involving interaction between ectodermally
derived odontogenic epithelium and neural crest–derived ectomesenchyme. CD56 is a neural cell
adhesion molecule with sparse information regarding its expression in tooth germs. Therefore,
the purpose of this study is to evaluate the immunohistochemical expression of CD56 in adenomatoid odontogenic tumor (AOT), ameloblastic fibroma (AF), and odontogenic myxoma (OMYX)
and to compare the staining pattern with the human tooth germs for histogenetic relationship.

Methods: Archival paraffin-embedded tissue blocks of 4 human tooth germs (one in bud stage,
4 in bud-to-cap transition stage, 3 in early bell stage, and 2 in late bell stage), 13 AOT, 4 AF, and
10 OMYX were evaluated by routine sections and immunohistochemistry with the CD56 marker.
Immunohistochemical reaction was assessed semi-quantitatively.

Results: Positive CD56 staining was observed on one side of the epithelium of the tooth bud
and in the outer enamel epithelium with a rim of positive reaction in the dental follicle. Other
components of the tooth germ were negative. Only certain tumor cells in AOT and AF reacted
to CD56 while OMYX did not react.

Conclusion: This study demonstrates the expression pattern of CD56 in human tooth germs
where the outer enamel epithelium adopts cell-fate decisions early in development. Thus, the
histogenetic correlation of cells positive for CD56 in AOT and AF implies that they are linked
to the dental lamina and/or outer enamel epithelium while the lack of CD56 expression in the
mesenchymal component of AF and OMYX is inconsistent with neural crest–derived mesenchyme participation.

Cite this article as: Ponniah I, Mathirat A. Expression of CD56 in human tooth germ, adenomatoid odontogenic tumor, and ameloblastic
fibroma. Essent Dent. 2025, 4, 0034, doi: 10.5152/EssentDent.2025.24034.