Abstract: Objective To investigate the clinical significance of plasma sST2 levels in patients with osteosarcoma. Methods From January 2012 to December 2016， preoperative plasma samples from 68 patients and postoperative plasma samples from 33 patients with osteosarcoma were collected. The plasma samples of 75 healthy subjects were selected as control. The levels of sST2 in the above samples were detected by enzyme linked immunosorbent assay. The difference of plasma sST2 levels between the preoperative samples and the healthy subjects and the changes of plasma sST2 levels before and after the operation of osteosarcoma were compared. The receiver operating characteristic curve （ROC） was used to evaluate the effectiveness of plasma sST2 levels in the early diagnosis of osteosarcoma. The relationship between plasma sST2 levels and clinicopathological features （sex， age， tumor site， Enneking stage， pathological subtype and AKP level） in osteosarcoma patients was further analyzed. Results The level of plasma sST2 in 68 patients with osteosarcoma was （392.71±176.93） pg／ml，higher than （67.61±32.47） pg／ml of 75 healthy subjects （P<0.05）. The postoperative level of plasma sST2 in 33 patients with osteosarcoma was （169.09±91.43） pg／ml， lower than （412.15±182.44） pg／ml of preoperative plasma specimens， and the difference was statistically significant （P<0.05）. ROC curve analysis showed that the area under the curve of sST2 in the diagnosis of osteosarcoma was 0.994 （95%CI：0.986-1.002）. When the cut-off value was 147.50 pg／ml， the sensitivity and specificity were 95.59% and 97.33%， respectively. Preoperative plasma sST2 levels are independent of gender， age， tumor location and pathological subtypes， but related with the Enneking stage and the level of AKP. The plasma level of sST2 was higher in stage Ⅲ than in stage Ⅱ， and compared with patients with the normal AKP， the plasma level of sST2 increased in patients with high-level AKP （P<0.05）.
Conclusion The plasma sST2 of patients with osteosarcoma increased and its level decreased after operation，and was associated with Enneking stage and AKP level. Preoperative level of sST2 may be related to the occurrence and development of osteosarcoma，which has a certain value in the evaluation and clinical diagnosis of osteosarcoma.