USE OF BIOMARKERS IN THE EVALUATION OF THYROID NODULES: IS THE KING NAKED

Hüda Ümit Gür^{1, *}, Akın Ünal², Muzaffer Akıncı¹, Ahmet Kocakuşak, Cemile Özdemir³, Ahmet Tarlacı³, Esma Yücetaş⁴, Macit Koldas⁴

¹University of Health Sciences Haseki Health Application and Research Center, General Surgery Clinic, Istanbul, Turkey - ²Avrasya Hospital, General Surgery Clinic, Istanbul, Turkey - ³University of Health Sciences Haseki Health Application and Research Center, Pathology Clinic, Istanbul, Turkey - ⁴University of Health Sciences Haseki Health Application and Research Center, Biochemistry Clinic, Istanbul, Turkey

Introduction: Preoperative discrimination of the thyroid nodules whether malignant or benign can reduce unnecessary surgery. Although fine needle aspiration biopsy (FNAB) is a frequently used decision-making procedure, it has some limitations. To date, many studies have been conducted to search for a biomarker in serum in order to predict malignancy in thyroid nodules. Tissue washout analysis could increase the reliability of a marker, because its level in the tissue is expected to be higher than serum. This prospective study was planned to evaluate whether the serum and washout values of galectin-3 (Gal-3), cytokeratin 19 (CK-19) and Hector Battifora Mesothelial Antigen-1 (HBME-1), which are used immunohistochemically in the diagnosis of thyroid cancer, would be useful in diagnosing thyroid cancer.

Method: The serum and washout values of biomarkers were prospectively compared in 43 patients who had previously had FNAB in General Surgery Clinic between September 2017 and February 2018 in whom total thyroidectomy or lobectomy were carried out. Serum and nodule FNAB washout fluid were compared by measuring Gal-3, CK-19 and HBME-1 values.

Results: In the statistical evaluation, there was no significant difference between the groups in terms of malignant or benign results according to the last pathology, except serum Gal-3 values according to FNAB results. According to the postoperative pathological results, patients were regrouped into papillary thyroid cancer and control group. When these groups were re-evaluated for the same biomarkers, the results were not statistically different. However, an unexpected negative relationship was established, revealing the unreliability of the markers.

Conclusion: It was concluded that Gal-3, CK-19 and HBME-1, which are highly immunohistochemically specific for diagnosis in differentiated thyroid cancers, are not useful as biomarkers.