Abstract

Introduction: Odontogenic keratocyst (OKC) and unicystic ameloblastoma (UA) are lesions of odontogenic origin. Both lesions are morphologically cysts. However, they are classified as developmental cysts and epithelial odontogenic tumours, respectively. Cyclin D1 (CCD1) dysregulation is associated with oncogenic activity and malignancies, while tumour protein p63 (p63) alterations are associated with tumourigenesis. Aim: To evaluate and compare the protein expression of CCD1 and p63 in sporadic OKC (OKC-sp), syndromic OKC (OKC-sy), and UA. Material and methods: 45 cases from the Anatomical Pathology Department, Faculty of Dentistry, University of Chile were analysed and divided into groups: OKC-sp (n = 15), OKC-sy (n = 15) and UA (n = 15), the latter categorised into intraluminal and/or luminal (n = 7) and mural (n = 8). Immunohistochemical staining for CCD1 and p63 proteins was performed from paraffin-embedded sections. Statistical analysis included the Shapiro–Wilk test, one-way ANOVA with Tukey's multiple comparisons, and Spearman's correlation coefficient (p < 0.05). Results: There was an involvement mainly in women in the mandibular area, and a high frequency of jaw expansion, especially in the mural UA. P63 protein expression was higher than CCD1 in all cystic lesions, particularly in mural UA (p < 0.001). No correlation was found between CCD1 and p63 expression. Conclusion: P63 may serve as a valuable marker for evaluating cell proliferative activity in odontogenic cystic lesions, providing insights into the aggressive behaviour of mural UA. © 2024 Sociedad Española de Anatomía Patológica