Introduction: Cytokeratin-19 (CK19), p53 and Ki-67 are some of the proposed markers for differentiating benign from malignant thyroid tumors.
Material and method: We evaluated the tissue expression of the three markers in 60 thyroid lesions including: 8 cases of nodular hyperplasia (NH), 16 follicular adenomas (FA), 26 papillary carcinomas (PC) and 10 follicular carcinomas (FC). Tissue sections fixed in formalin and embedded in paraffin were immunohistochemically (IHC) stained (LSAB technique, visualization with DAB) using monoclonal antibodies anti-CK19 (clone RCK 108), anti-Ki67 (clone MIB-1) and anti-p53 (clone DO-7); the data were statistically analyzed using the unpaired T-test.
Results: CK19 was significantly expressed only in PC≥20 (P<0.001). For p53 and Ki-67 the results of statistical analysis were not significant for the compared pairs.
Conclusions: CK19 is useful in differentiating the follicular variant of PC from FC and PC from the papillary aspects in NH. Immunoreactivity of p53 and Ki-67 was not proven to be useful in differentiating PC from NH, the results being statistically insignificant.