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

Background: Odontogenesis is a multistage process involving interaction between ectodermallyderived odontogenic epithelium and neural crest–derived ectomesenchyme. CD56 is a neural celladhesion 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, and10 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 budand in the outer enamel epithelium with a rim of positive reaction in the dental follicle. Othercomponents of the tooth germ were negative. Only certain tumor cells in AOT and AF reactedto CD56 while OMYX did not react.Conclusion: This study demonstrates the expression pattern of CD56 in human tooth germswhere the outer enamel epithelium adopts cell-fate decisions early in development. Thus, thehistogenetic correlation of cells positive for CD56 in AOT and AF implies that they are linkedto the dental lamina and/or outer enamel epithelium while the lack of CD56 expression in themesenchymal 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 ameloblasticfibroma. Essent Dent. 2025, 4, 0034, doi: 10.5152/EssentDent.2025.24034.