Investigation of tert mutation frequency in papillary microcarcinomas; relationship with histopathological subtype and clinicopathological findings

Purpose: In the 2017 World Health Organization classification, papillary carcinomas ≤1 cm are called microcarcinomas and their incidence is increasing gradually. Although their biological behavior is generally fine, aggressive cases have also been reported. In recent years, active surveillance has been recommended as an option by avoiding surgical treatment. For this reason, in microcarcinomas the detection of molecular changes which can predict aggressiveness has gained importance and studies are still quite limited. Our study aims to detect changes in the TERT promoter gene alterations in papillary microcarcinomas, whose prognostic importance is reported, by examining histomorphological features and subtypes, and to show the correlation of all these findings with clinicopathological findings in the presence of BRAF gene mutation. Materials and Methods: 95 papillary microcarcinoma cases diagnosed in Çukurova University Faculty of Medicine, Department of Pathology between 2010-2019 were included in the study. The presence of TERT expression was investigated by RT-PCR method, and its relationship with histomorphological and clinicopathological findings was evaluated. In addition, patients who performed BRAF by immunohistochemical method were evaluated and correlations between both genes and in terms of histomorphological and clinicopathological findings were analyzed. Results: A statistically significant correlation was found between multifocality, extrathyroidal extension, and tumor size of ≥0.5 cm and lymph node metastasis. No relationship was found between TERT expression and any clinicopathological finding. A statistically significant association of BRAF V600E mutation with lymph node metastasis, lymphovascular invasion, advanced disease stage and classical subtype has been demonstrated. Conclusion: Low mortality rates in papillary carcinomas have not changed for many years. Therefore, the requirement of surgical treatment in microcarcinoma cases is controversial. The ability of molecular markers to predict prognosis will be effective in reducing unnecessary surgery. The correlation of TERT mutations with aggressiveness in thyroid cancers is also holding promise for papillary microcarcinomas. Limited number of studies on this area are also available in the literature. Although TERT expression was detected in some cases in our study, its relationship with clinicopathological findings could not be demonstrated. This result is consistent with the literature and has been evaluated as a result of the TERT molecule taking a role in the advanced stages of carcinogenesis. Keywords: Papillary Microcarcinoma, TERT, BRAF