ObjectiveTo investigate the predictive value of serum levels of galectin-1 (Gal-1) and soluble B7-H4 (sB7-H4) in postoperative metastasis of papillary thyroid carcinoma (PTC) patients.MethodsFrom February 2020 to February 2022, 126 PTC patients admitted to our hospital who underwent total thyroidectomy and neck lymph node dissection were collected, and according to postoperative pathological examination for metastasis, patients were divided into metastasis group (37 cases) and non metastasis group (89 cases), 108 volunteers who entered our hospital for physical examination were included as the control group. Enzyme linked immunosorbent assay (ELISA) was applied to detect the levels of Gal-1 and sB7-H4 in serum; Spearman method was applied to analyze the correlation between serum levels of Gal-1 and sB7-H4 and postoperative metastasis in PTC patients; Relevant factors affecting postoperative metastasis in patients with PTC were analyzed by multifactorial Logistic regression; diagnostic value of combined Gal-1 and sB7-H4 assay for postoperative metastasis in PTC patients was analyzed by ROC curve; Clinical utility of serum Gal-1 and sB7-H4 levels and combined assays for predicting the development of metastases after surgery in patients with PTC was analyzed using a DCA.ResultsThe serum levels of Gal-1 and sB7-H4 in PTC patients were obviously higher than those in the control group (P<0.05); The serum levels of Gal-1 and sB7-H4 in PTC patients in postoperative metastasis group were obviously higher than those in the non metastasis group (P<0.05); the serum levels of Gal-1 and sB7-H4 in PTC patients were positively correlated with postoperative metastasis (r: 0.623, 0.682, P<0.05); the levels of Gal-1 and sB7-H4 in serum were risk factors for postoperative metastasis in PTC patients (P<0.05); the area under the curve (AUC) of the combined prediction of Gal-1 and sB7-H4 for postoperative metastasis in PTC patients was 0.869, which was superior to their individual detection (Z_{combination-Gal-1}=2.012, Z_{combination-sB7-H4}=2.014, P: 0.044, 0.044), the sensitivity was 89.19%, and the specificity was 69.66%; The results of DCA curves showed that the net benefit of the combined serum Gal-1 and sB7-H4 test in predicting the risk of postoperative metastasis in patients with PTC was superior to that of the two tests alone when the high-risk thresholds ranged from 0.08 to 0.97, and the calibration curve showed good fitting effect, with a slope close to 1.ConclusionThe serum levels of Gal-1 and sB7-H4 in patients are closely related to postoperative metastasis in PTC patients, and the combined examination of the two can assist clinical practice in effectively predicting postoperative metastasis in PTC patients.