Recorrência do ameloblastoma: análise de fatores clínicoradiográficos e imunoexpressão de hMSH2, hMLH1 e KI-67

Abstract

Introduction: Ameloblastoma is a benign odontogenic neoplasm, which has high rates of postoperative recurrence. Several studies show the relationship between clinicopathological characteristics and treatment modalities in ameloblastoma recurrence. The molecular mechanisms involved in the etiopathogenesis of this tumor are little known, and although changes in the Mismatch System favor the development of different human neoplasms, their importance in the development of ameloblastoma still remains poorly understood. Objective: To identify clinical and pathological factors associated with ameloblastoma recurrence, as well as to investigate the role of immunoexpression of hMLH1, hMSH2 and Ki-67 proteins in the recurrence of these odontogenic tumors. Methodology: This was a descriptive, cross-sectional and retrospective study, with a sample consisting of 22 cases of recurrent ameloblastoma and 22 non-recurrent cases. Immunohistochemical analysis was performed quantitatively, considering the cellular (nuclear) location of the studied proteins. McNemar's test was used to compare variables between 1 st biopsy and recurrent AMB lesions. Recurrence-free survival was analyzed using the Kaplan-Meier method and survival functions were compared according to variables using the log-rank test. Results: The most affected gender was female (n=24; 54.5%), with a mean age of involvement of 39.1 ± 19.8 years, 45.5% (n=20) being white. The posterior region of the mandible was the most frequent in the relapsed group (n=18, 81.8%) and also for the cases that did not present recurrences (n=16, 72.8%). Recurrence-free time was 50.0 (34.5 – 63.6) months. Factors significantly associated with recurrence of AMBs were: presence of cortical expansion (p=0.0089), absence of bone reconstruction (p=0.018), conservative treatment (p=0.021), loss of hMSH2 immunoexpression (p=0.006) and hMLH1 (p=0.038) and strong Ki-67 immunoexpression (p=0.029). Conclusion: Based on the findings of this research, radiographic appearance, treatment modality and immunoexpression of proteins from the Mismatch System and Ki-67 can be used as indicators for recurrence in ameloblastomas.