Abstract

Objective: In this study, we aimed to study BRAFV600E and NRAS mutations among thyroid tumor patients in the Mongolian population.

Methods: Immunohistochemical staining was performed using CD56 antibodies on 59 formalin-fixed paraffinembedded (FFPE) tissue sections. DNA extractions from FFPE and fresh thyroid tumor tissues were extracted using a genomic DNA kit. An ABI 3730xl genetic analyzer was used for DNA sequencing.

Results: The thyroid tumors of 59 patients were studied. These patients were predominantly female (53, 89.8%), and the mean age was 45.61±14.2 years (range 13–72 years). Of these cases, 46 (78%), 3 (5.1%), and 8 (13.61%) were diagnosed as PTC, FTC, and follicular adenoma, respectively, by histology. Immunohistochemistry analysis found that CD56 was expressed in 7 (87.5%) benign tumors and 14 (27.5%) malignant tumors, and the difference was significant (p=0.002). In cases of PTC, the BRAFV600E mutation was positive in 9 (19.6%) cases, while the NRAS mutation was positive in 2 (3.38%) cases. However, the manifestations of these mutations are not significantly associated with the clinic pathological features of PTC.

Conclusion: BRAFV600E and NRAS mutations occurred at a relatively low rate and were not correlated with increased PTC aggressiveness in our study.