COL18A1 and differentiated thyroid carcinoma: <h4>Background</h4>To explore the correlation of serum soluble interleukin-2 receptor (sIL-2R), vascular endothelial growth factor (VEGF), and endostatin (ES) with estrogen levels in papillary thyroid carcinoma (PTC) patients, and to assess the predictive efficacy of these biomarkers for PTC diagnosis and postoperative recurrence.<h4>Methods</h4>From March 2023 to March 2024, 132 newly diagnosed PTC patients and 128 healthy controls were enrolled.