Expressão de calretinina em tumores odontogênicos epiteliais benignos e malignos

Abstract

Odontogenic tumors (OTs) are a group of heterogeneous lesions whose morphological complexity and variable behavior have motivated the search for diagnosis and prognosis markers. Calretinin is a calcium-biding protein that presents imunorreactivity for odontogenic epithelium and has been identified in OTs with ameloblastic differentiation. The aim of this study was to assess the expression of calretinin in different OTs in order to evaluate its applicability as an adjunct data in the differential diagnosis of these lesions and in the definition of prognosis. A total of 17 cases of ameloblastoma (AME), seven unicystic ameloblastomas (UAME), six adenomatoid odontogenic tumors (AOT), 15 ameloblastic carcinomas (AMECA) and five clear cell odontogenic carcinomas (CCOC) were assessed. Immunohistochemical assays were performed with estreptavidin-biotin-peroxidase technique with polyclonal rabbit anticalretinin antibody. Analysis of immunostaining was performed with Quickscore method, translating the product of the proportion of positive cells by the intensity of stain in the cytoplasm and nucleus of central and peripheral cells. Calretinin expression was observed in 14 AMEs, three UAMEs, eight AMECAs and three CCOCs, mainly located in the cytoplasm of central cells and with higher intensity in areas of squamous and granular metaplasia. Data analysis demonstrated significant differences in the distribution of positive cases among carcinomas and ameloblastomas in comparison with AOT and between aggressive and non-aggressive lesions. Similar results were observed in the Quickscore analysis. In conclusion, calretinin can be considered a specific marker for de differential diagnosis of ameloblastomas and carcinomas with AOT and for the differentiation between aggressive and non-aggressive lesions.