Background: The challenging target in the workup of thyroid nodule(s) is to exclude or diagnose thyroid cancer efficiently prior to surgical intervention. The present work studied a panel of eight serum biomarkers to differentiate benign from malignant thyroid nodules, aiming at reducing unnecessary thyroidectomy performed for inconclusive preoperative fine needle aspiration cytology. Serum interleukin-5 (IL-5), interleukin-8 (IL-8), hepatocyte growth factor (HGF), epidermal growth factor (EGF), angiopietin (Ang1), nonokine induced by interferon gamma (MIG), galectin (Gal-3), and vitamin D-binding protein (VDRP) were quantified by multiplex bead assay using Luminex xMAP technology. The study was conducted on 60 subjects of three groups (20 each; healthy controls, benign thyroid nodule, and malignant thyroid nodule).

Results: Significant increase of the following biomarkers in the malignant group compared to the benign group was found; IL-8: 29.7 vs 8.75 pg/ml, p < 0.001, EGF: 128.7 vs 6.72 pg/ml, p < 0.001, HGF: 173.2 vs 112.2 pg/ml, p = 0.012, MIG: 776.7 vs 438 pg/ml, p = 0.023, and Ang-1: 95016 vs 33327.5 pg/ml, p = 0.014. No significant differences were detected for IL-5, Gal-3, and VDBP. Serum IL-8 and EGF showed the highest diagnostic performance individually with area under the curve (AUC) 0.849 and 0.848, respectively. The combined biomarker panels of IL-8 and EGF and IL-8, EGF, and MIG have reached a sensitivity and specificity of 95% and 65%, respectively, with a negative predictive value of 92.9%.

Conclusions: Serum IL-8 and EGF individually or the combined biomarker panel of IL-8, EGF, and MIG are promising tests that can help to exclude malignancy in thyroid nodule workup.