Serum cytokeratins determination in differentiated thyroid carcinoma

To assess the potential value of cytokeratins (CK) 8,18,19 as tumor markers for thyroid diseases, a study was performed comparing serum CK 8,18,19 levels in patients affected from thyroid carcinoma, adenoma, other benign thyroid diseases and healthy volunteers as controls. One hundred cases (65 patients and 35 controls) were examined. Thirty patients had thyroid carcinoma (18 papillary--PTC, 8 follicular--FTC, 4 medullary--MTC), 19 non-toxic goiter, 10 thyroid adenoma, 6 chronic thyroiditis and 35 healthy volunteers as controls. These controls were matched by age and sex. The mean value of CK in benign thyroid diseases (46.1 U/L) was significantly higher (p<0.02) than that in healthy controls (29.6 U/L). The mean value of CK in carcinomas (68.1 U/L) was significantly higher than that in healthy controls (p<0.01) and benign thyroid diseases patients (p<0.05). The positive rate of CK in thyroid carcinomas was 28.1%, while in benign thyroid diseases was 17.8%. The CK sensitivity for thyroid carcinomas was 28.1%, with a specificity of 80% and accuracy of 70.4%. In PTC patients the mean CK value was not significantly higher than in the benign diseases' group and in healthy subjects. No evident correlation between CK levels and tumor mass was found. In FTC patients the mean value was significantly higher than in the benign diseases' group and in healthy subjects. Large tumors showed the highest levels, while small tumor values were similar to the control ones. In MTC patients the mean value was significantly higher than in the benign diseases' group and in healthy subjects, with the highest peaks in large tumors and metastatic tumors. The detection of increased values in thyroid carcinomas with high metastatic potential (FTC and MTC) seems to confirm the role of these antigens in predicting the malignancy's degree of the neoplasm. These findings, if confirmed in larger series, could play an important role in assessing the CK 8,18,19 serum level as a real prognostic factor. Further repeated serum determinations after total thyroidectomy might indicate the role of CK 8,18,19 as serum markers predicting the risk of metastases.