Avaliação da expressão imuno-histoquímica das proteínas p53 e pRB em ameloblastomas e tumores odontogênicos queratocísticos / Evaluation of immunohistochemistry expression of the proteins p53 and pRB in ameloblastomas and keratocystic odontogenic tumorP

Tumores odontogênicos constituem grupo abrangente de afecções tumorais, sendo ameloblastomas e tumores odontogênicos queratocísticos as lesões benignas de maior frequência, cujas características biológicas são pouco conhecidas. Objetivo do presente estudo foi avaliar o perfil imuno-histoquímico das proteínas pRB e p53 em ameloblastoma e tumor odontogênico queratocístico. Foram avaliadas amostras de material parafinado de 21 casos de ameloblastoma e de 20 casos de tumor odontogênico queratocístico para ensaio de imuno-histoquímica com os anticorpos anti-pRB e anti-p53. A contagem da imuno-marcação foi realizada a partir de fotografias de alta resolução processadas no software ImageJ para quantificação manual em campo de 1000 células. A localização da imuno-marcação para ambos anticorpos foi semelhante, sendo em ameloblastomas predominantemente nas células da periferia e, em tumores odontogênicos queratocísticos, nas camadas suprabasais. Quantitativamente, as porcentagens de células marcadas foram estatisticamente maior nos ameloblastoma para anti-p53 (p=0,01) e maior nos tumores odontogênicos queratocísticos para anti-pRB (p=0,04). Não houve correlação estatística entre a porcentagem de células marcadas para anti-p53 e anti-pRB nos ameloblastomas, porém, esta correlação foi positiva e moderada nos tumores odontogênicos queratocísticos (r=0,537; p=0,018). Nota-se ligeira diferença na quantificação das imuno-marcações para o anti-p53 e anti-pRB. Tais resultados devem ser ponderados pela reduzida casuística, porém, sugerem perfis distintos em mecanismos biológicos determinantes para ambos os tumores.

Odontogenic tumors are a comprehensive group of tumor diseases, being ameloblastomas and keratocystic odontogenic tumors the most frequent benign odontogenic tumors. Their biological characteristics are little unknown. The aim of present study was to evaluate the immunohistochemical profile of pRB and p53 proteins in 21 cases of ameloblastomas and 20 cases of keratocystic odontogenic tumors for anti-pRB and anti-p53 antibodies. The quantification of immunostaining was performed manually with high-resolution photographs processed in the ImageJ software to quantify positive cells in a 1000 cells-field. The location of immunostaining for both antibodies was similar. In ameloblastomas, positive cells are located mainly in the peripheral layers, whereas in keratocystic odontogenic tumors the positive cells are located in the suprabasal layers. Quantitatively, the percentage of labeled cells was statistically higher in ameloblastomas for anti-p53 (p = 0.01) and higher in keratocystic odontogenic tumors for anti-pRB (p = 0.04). There was no statistical correlation between the percentage of labeled cells to anti-p53 and anti-pRB in ameloblastomas, however, its correlation was positive and moderate in keratocystic odontogenic tumors (r = 0.537; p = 0.018). It is possible to identify a slight difference in immuno-quantification for anti-p53 and anti-pRB among these lesions. These results must be pondered by the small sample, however, is suggests a different profile in a preponderant key biological mechanisms for odontogenic tumors.

Jaw osteonecrosis in patients receiving bisphosphonate therapy: results from a single institution

A growing number of reported cases of jaw osteonecrosis in patients receiving bisphosphonate have been published in the last several years. The clinical features of this condition include pain, paresthesia, bone exposure and fistula. Risk factors have been recognized and classified as local and/or systemic. Objective: The aim of this study was to demonstrate the clinical data of the patients with osteonecrosis assisted at a single institution. Patients and Methods: A total of 42 patients presenting 49 areas of jaw osteonecrosis were evaluated. Medical records were analyzed in order to collect information on underlying disease, bisphosphonate information, clinical features related to bisphosphonate-induced osteonecrosis of the jaw, as well as precipitating events related to its occurrence. Results: Most patients were female (71%) and the mean age was 64.7 years old. Breast cancer was the most frequent underlying disease (40.5%) followed by multiple myeloma, prostate cancer, lung and osteoporosis. In addition, the average use of bisphosphonate was 36.8 months and most patients had received zoledronic acid. The posterior region of the mandible was the main affected site. Among the possible triggering factors, exodontias was associated with 73.8% of the cases. The treatment modalities consisted of surgical, local irrigation with clorexidin and antibiotics and a majority of cases presented complete or partial remission. Conclusion: Most cases of jaw osteonecrosis were related to tooth extraction and surgical interventions showed a good control of the osteonecrosis cases.