Odontogenic Keratocyst, Orthokeratinized Odontogenic Cyst and Epidermal Cyst: An Immunohistochemical Study Including Markers of Proliferation, Cytokeratin and Apoptosis Related Factors

Abstract

Objective: There are microscopic similarities among odontogenic keratocyst (OKC), orthokeratinized odontogenic keratocyst (DOC) and epidermal cyst (EDC). This study was to compare with cell proliferation, cell differentiation and apoptosis related factors in OKC, DOC and EDC in order to clarify the characters and category of three hitstopathologically similar cysts.Material and Methods: Fourteen cases of OKC, nine cases of DOC and eighteen cases ofEDC were examined immunohistochemically using antibodies against cytokeratins (CK7,10, 10/13,17,18,19,20) and apoptosis related factors (bcl-2 and Bax).Results: Ki-67 labeling index in OKC was statistically higher than that in DOC and EDC (p<0.05). And that in DOC was higher in EDC (p<0.05). In OKC, CKs and bcl-2 expression patterns were different from DOC and EDC, while both DOC and EDC showed similar reactivity with CKs and bcl-2.Conclusions: The present results suggested that OKC had high cellular proliferation and was relatively low differentiation as compare with DOC and EDC. In addition, there was participation of apoptosis suppressor in OKC. The character of DOC occupied an intermediate position between OKC and EDC. Therefore, it was possible to consider DOC as a distinct entity from OKC. EDC had the lowest cellular activity in the three cysts and it was comparatively maturated lesion.

Comparative study of cytokeratin and langerin expression in keratinized cystic lesions of the oral and maxillofacial regions

“…However, Tsuji et al (27) and Hayashi et al (28) reported that CK13 expression could not be confirmed in OOCs, being inconsistent with our present result. On the other hand, Koizumi (29) stated that CK13 was partially positive in OOCs, supporting of our result. In addition, Crivelini et al (30) described that CK13 expression in odontogenic epithelium was consistent with its expression in dental lamina.…”

“…Immunoreactivity for CK17 was found in all layers except for the basal layer in both OOCs and DCs, whereas it was partially weak but present in all layers in KCOTs, suggesting that KCOT has a more neoplastic nature. CK19 (40 kDa) is expressed in dental lamina, the enamel organ and epithelial rests of Malassez, suggesting that it may be considered an odontogenic epithelial marker (29,(33)(34)(35). In fact, several reports have indicated that CK19 is positive in the basal layer of non-keratinized epithelium, or was negative in KCOTs (25,29).…”

“…In a comparison between OOCs as representative of developmental cysts and KCOTs as neoplastic cystic lesions, differences in expression were evident among CK10, CK17, and CK19. CK10 (56.5 kDa) is expressed in keratinized stratified squamous epithelium, except for the basal layer (25,27,29). CK10 positivity was evident in the Su and SP of OOCs, indicating they differ from lesions such as KCOTs and DCs.…”

“…In addition, Crivelini et al (30) described that CK13 expression in odontogenic epithelium was consistent with its expression in dental lamina. Furthermore, several reports have indicated that CK13 is positive in lesions derived from odontogenic epithelium, such as radicular cysts, DCs, ameloblastomas and KCOTs (24)(25)(26)(27)(28)(29). CK17 (46 kDa) is expressed in the anlage of sweat glands, hair follicles and teeth (31), and also in lesions such as odontogenic cysts and tumors (24)(25)(26)32).…”

“…CK19 (40 kDa) is expressed in dental lamina, the enamel organ and epithelial rests of Malassez, suggesting that it may be considered an odontogenic epithelial marker (29,(33)(34)(35). In fact, several reports have indicated that CK19 is positive in the basal layer of non-keratinized epithelium, or was negative in KCOTs (25,29). However, our present study showed that CK19 was negative in OOCs, suggesting that CK19 might not be a specific odontogenic marker, whereas positivity was evident in all layers except for the basal layer in KCOTs (80%) and DCs (90%).…”