Amelogenin in calcified matrices of odontogenic cysts and odontogenic tumors: An immunohistochemical study

Abstract

Background/purpose: There are few studies comparing the expression of enamel proteins, such as amelogenin, and cytokeratins in cyst and odontogenic tumors like in ameloblastoma and odontogenic keratocyst, indicating that amelogenin could be a potential biomarker for the aggressiveness in the odontogenic tumors. The aim of this study was to evaluate if the expression of amelogenin, cytokeratin AE1/AE3 (CKAE1/AE3) and cytokeratin 14 (CK14) in cysts and odontogenic tumors with calcified matrices such as calcifying odontogenic cyst (COC), compound (CdO) and complex (CxO) odontomas, adenomatoid odontogenic tumor (AOT) and calcifying epithelial odontogenic tumor (CEOT) as an aggressiveness indicator.

Materials and methods: Three COC, eight CxO, three CdO, twelve AOT, two CEOT and three dental germs were submitted to an immunohistochemistry panel of antibodies composed of amelogenin, CKAE1/AE3 and CK14.

Results: CKAE1/AE3 and CK14 was present in all odontogenic epithelia. The amelogenin protein was detected in prismatic and amorphous calcified matrices of epithelial origin belonging to CxO, CdO, AOT, COC and the tooth germs used as controls. On the other hand, the CEOT was the only tumor or cyst studied that did not present immunostaining for amelogenin in calcified matrices.

Conclusion: Amelogenin was detected in pathologies with a low or absent recurrence rate and excellent prognosis. CEOT was the lesion of greater clinical aggressiveness which did not express amelogenin. The presence of amelogenin in calcified matrices of odontogenic arise could be an indicator of low aggressiveness.

Keywords: Amelogenin; Cytokeratin; Immunohistochemistry; Odontogenic cysts; Odontogenic tumors.

Figure 1

Amelogenin immunohistochemical staining in different odontogenic tumors (CxO,CdO, CEOT, AOT), COC and dental germ. A. Dental germ, with a positive immunostaining for enamel matrix formation, ×40 (control amelogenin); B. Complex Odontoma, with a positive immunostaining for enamel matrix formation, x40; C. Compound Odontoma, with a positive immunostaining for enamel matrix formation, x40; D. AOT, moderate immunostaining for amelogenin for the calcification indicate amelogenin presence, x40; E.CEOT, negative immunostaining for amelogenin, x40; F. COC, positive immunostaining for amelogenin in the ghost cells, x40. ∗ sa: secretory ameloblast, em: enamel matrix, sr: stellate reticulum.

Figure 2

Cytokeratin AE1/AE3 immunohistochemical staining in different odontogenic tumors (CxO, CEOT, AOT), COC and dental germ. A. Dental germ, with a positive immunostaining for epithelial cell (ameloblast),x40.; B. Complex Odontoma, with a positive immunostaining for epithelial cells (reduced epithelium of enamel organ), x40.; C. Compound Odontoma, with a positive immunostaining for epithelial cells (reduced epithelium of enamel organ), x40; D. AOT, positive immunostaining for epithelial component (rosette, duct-type structure), x40; E. CEOT, positive immunostaining for epithelial cells, x40; F. COC, positive immunostaining for the epithelial and ghost cells, x40. ∗ am: ameloblast, em: enamel matrix, sr: stellate reticulum, ie: intermediate epithelium.

Figure 3

Cytokeratin 14 immunohistochemical staining in different odontogenic tumors (CxO, CEOT, AOT), COC and dental germ. A. Dental germ, with a positive immunostaining for epithelial cells, x40.; B. Complex Odontoma, with a positive immunostaining for epithelial cells, x40.; C. Compound Odontoma, with a positive immunostaining for ameloblastic epithelium, x40; D. AOT, mild positive immunostaining for basal epithelial cells of rossete and duct-type structure, x40; E. CEOT, positive immunostaining for CK14 in the epithelial cells, x40.; F. COC, positive immunostaining for the epithelial cells and negative in ghost cells (arrowhead), x40. ∗ am: ameloblasts, em: enamel matrix, sr: stellate reticulum, ie: intermediate epithelium,. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)