High Local and Systemic Expression of Pentraxin-3 in Anaplastic Thyroid Cancer

Background and objectives: Chronic inflammation plays a key role in cancer patho-genesis. Long pentraxin 3 (PTX3) is an inflammatory protein implicated in tumor pro-gression. Aggressive thyroid cancer is associated with immune infiltration and sys-temic inflammation. This study evaluates PTX3 plasma levels in patients with non-medullary thyroid cancer (TC) compared to benign thyroid diseases and investi-gates its tissue expression. Methods: We prospectively included 55 TC patients (41 preoperative, 14 recurrent) with various subtypes: 42 papillary, 3 follicular, 4 oncocyt-ic, 4 anaplastic (ATC), and 2 poorly differentiated (PDTC). A control group of 32 pa-tients with benign thyroid diseases (20 goiter, 12 autoimmune thyroiditis) was includ-ed. PTX3 plasma concentrations were measured by ELISA, and tissue expression of PTX3 and CD68, a macrophage marker, was analyzed using immunohistochemistry. Results: PTX3 plasma levels did not significantly differ between TC and controls, but patients with PDTC and ATC had markedly higher concentrations. Tissue analysis showed strong PTX3 expression in three of four ATC cases in tumor and stromal cells, whereas benign and differentiated thyroid tissues exhibited minimal staining. CD68 expression was positive in ATC, indicating tumor-associated macrophage infiltration. However, few cells were double-positive for PTX3 and CD68, suggesting PTX3 origi-nates from tumor, stromal cells, or other immune cells rather than macrophages. Conclusions: Our findings suggest that PTX3 is associated with aggressive thyroid cancer, particularly ATC. Further studies are needed to elucidate its role in tumor progression and the inflammatory microenvironment.