Abstract: Objective To explore the relationship between serum interleukin-6 (IL-6), high mobility group protein A2 (HMGA2), stimulated by retinoic acid 6 (STRA6) with the clinical pathological features and postoperative lymph node metastasis of differentiated thyroid cancer (DTC) patients.Methods From March 2021 to July 2024, 84 DTC patients in our hospital were designated as the DTC group, and another 97 patients with benign thyroid diseases were designated as the benign group.The DTC patients was assigned into non metastatic group (n=60) and metastatic group (n=24) based on lymph node metastasis within 6 months after surgery.Enzyme-linked immunosorbent assay was used to detect serum IL-6, HMGA2, and STRA6.The correlation analysis was conducted using Spearman's method.Receiver operating characteristic (ROC) curve was used to explore the predictive efficacy of serum IL-6, HMGA2, and STRA6 for postoperative lymph node metastasis in DTC patients.Results Compared with the benign group, the levels of serum IL-6 [(188.47±31.14) vs (152.35±25.09) pg/ml], HMGA2 [(11.23±2.25) vs (6.07±1.34) ng/ml], and STRA6 [(95.09±14.89) vs (65.16±10.28) ng/ml] were higher in the DTC group (P < 0.05).Spearman analysis showed that serum IL-6, HMGA2, and STRA6 correlated with TNM staging in DTC patients (P<0.05).There was a statistically significant difference in the maximum tumor diameter and TNM stage between the metastasis group and the non-metastasis group (P<0.05).For the non metastatic group, the metastatic group had higher preoperative and postoperative serum IL-6, HMGA2, and STRA6 (P<0.05).ROC analysis showed that the joint of serum IL-6, HMGA2, and STRA6 had a higher area under the curve (AUC) (0.926) in predicting postoperative lymph node metastasis in DTC than the individual predictions of IL-6 (Z=2.514, P=0.012), HMGA2 (Z=2.089, P=0.037), and STRA6 (Z=2.008, P=0.045).Conclusion The levels of IL-6, HMGA2 and STRA6 in the serum of DTC patients are relatively high and are related to the TNM stage of the patients, and the combination of the three has a high predictive value for lymph node metastasis after surgery in DTC patients.

Key words: differentiated thyroid cancer; clinical pathological features; lymph node metastasis; interleukin-6; high mobility group protein A2; stimulated by retinoic acid 6