This is an non-randomised retrospective study consisting of 2 parts. Part A. Histological specimens (formalin fixed paraffin embedded) of patients who were operated on for benign and malignant thyroid disorders will undergo molecular testing to create a molecular profile of thyroid nodules characteristic of Belarusian population.~Part B. Fixed cytological smears of indeterminate thyroid nodules (categories III, IV and V according to Bethesda scoring system) of operated patients will undergo molecular testing to evaluate the possibility and reliability of molecular testing of fixed cytological smears using available assays.
Profiling and comparative analysis of genomic alterations and miRNA expression in benign and malignant thyroid tumors using histological and cytological specimens will be performed. Obtained information is necessary to create a molecular test to refine the cancer risk of cytologically indeterminate thyroid nodules.