TNF-α May Exert Different Antitumor Effects in Response to Radioactive Iodine Therapy in Papillary Thyroid Cancer with/without Autoimmune Thyroiditis.

Autoimmune thyroiditis (AIT) may impair radioiodine (131I) uptake in papillary thyroid cancer (PTC). Finding the mechanisms that govern immune cells during 131I therapy of PTC with concomitant AIT (PTC + AIT) could provide a rationale. Our study aimed to evaluate the effects of 131I on anti-thyroglobulin antibodies (TgAb), matrix metalloproteinase-9 (MMP-9) and its tissue inhibitor TIMP-1 and tumor necrosis factor-α (TNF-α) and its receptors TNFR1 and TNFR2, in PTC and PTC + AIT patients. Peripheral blood was collected from 56 female patients with PTC and 32 with PTC + AIT before and 4 days after 131I (3.7 GBq). The serum levels of TgAb, MMP-9, TIMP-1, TNF-α, TNFR1 and TNFR2 were measured by ELISA. The mean radioactivity of blood samples collected after 131I intake was higher in the PTC + AIT group than in PTC (p < 0.001). In the PTC + AIT group, TNF-α/TNFR1 and TNF-α/TNFR2 ratios decreased by 0.38-fold and 0.32-fold after 131I and were positively correlated with the MMP-9/TIMP-1 ratio (r = 0.48, p = 0.005, and r = 0.46, p = 0.007). In the PTC group, TNF-α/TNFR1 and TNF-α/TNFR2 ratios increased by 3.17-fold and 3.33-fold and were negatively correlated with the MMP-9/TIMP-1 ratio (r = -0.62, p < 0.001 and r = -0.58, p < 0.001). Our results demonstrate that TNF-α may exert different antitumor effects in response to 131I therapy depending on the patient's immune profile.