Cell proliferation and apoptosis immunolocalisation suggest an association between aggressiveness and the preferred location of mural unicystic ameloblastomas: A multicentricStudy

Abstract Objectives This study aimed to assess whether the different biological behaviour between subtypes of unicystic ameloblastoma (UA) are related to the expression of proteins that modulate cell proliferation and apoptosis. Materials and methods Immunohistochemical study with a sample of 32 cases of UA, 11 cases of conventional ameloblastoma (CAM) and 10 dental follicles (DF) cases was performed. Cell proliferation was assessed using Ki-67 status and apoptosis by expression of Caspase-3. Positive cells were quantified in each sample and the difference among groups was compared. Results Mural UA (MUA) showed a higher immunostaining of Ki-67 (p < 0.05) and a lower immunostaining of Caspase-3 (p < 0.05) compared to luminal and intraluminal subtypes of UA (LIUA) and CAM. For both proteins, the LIUA and CAM groups showed no statistical difference. The neoplastic cells of the cystic capsule of the MUA showed a higher expression of Ki-67 protein (p < 0.0001) and a lower expression of Caspase-3 (p < 0.0001) compared to the lumen. DF showed lower Ki-67 and Caspase-3 immunostaining (p < 0.05) than neoplasms, except when comparing Caspase-3 expression between DF and MUA, as there was no statistical difference. Conclusions The higher immunoexpression of Ki-67 and lower of Caspase-3 in MUA, in the parenchyma cells inside the cystic capsule, suggests an association between the biological behaviour and the location of neoplastic cells in the tumour.