The value of tumor markers in the diagnosis of papillary thyroid carcinoma alone and in combination.

Aim of the study is to evaluate the expression of CK19, galectin-3, HBME-1, CD56, claudin-1 and neutrophil gelatinase-associated lipocalin (NGAL) in papillary thyroid carcinoma (PTC), including classic, follicular variant and micro-carcinoma. Peritumoral benign thyroid tissues were used as a control (C). Immunohistochemical staining with the EnVision detection system was performed on 59 formalin-fixed, paraffin-embedded thyroid tissues, including 43 PTC and 16 C. CK19, galectin-3, HBME-1, claudin-1 and NGAL were positive in most PTC, but were negative or showed focal weak staining in C. CD56 was positive in C, but absent in PTC. For a single analyzed tumor marker, the sensitivity of the above six thyroid tumor markers was 100%, 95.3%, 86%, 79.1%, 90.7%, 93%, respectively. The specificity was 56.25%, 100%, 100%, 100%, 100%, 100%, respectively. For the combination of the six tumor markers, the sensitivity, specificity, positive predictive value, negative predictive value and the diagnostic accuracy were all 100%, with co-expression of at least four indices. In the diagnosis of PTC, combined application of the above tumor markers is recommended. It can be diagnosed as PTC clearly when thyroid lesions are positive for at least four of the above tumor markers [CD56⁻], and can be excluded as PTC definitely when at least four tumor markers are negative [CD56⁺].