1. Serum concentration of IL-2, IL-6R, IL-8, and IL-12 might assist in the characterization of thyroid nodules' malignancy and tumor aggressiveness.2. Concentration of serum IL-8 was higher in the malignant group compared with controls.3. IL-6 and IL-10 were not able to discriminate the benign and malignant groups from controls.4. Serum concentrations of IL-2, 2R and 10 were associated with thyroglobulin levels. The gene discussed is IL2; the disease is neoplasm.