Abstract: Objective To investigate the expression of long non-coding RNA （lncRNA）zine finger antisense 1（ZFAS1） in osteosarcoma tissues and its influence on patient prognosis. Methods A total of 101 patients with osteosarcoma who were hospitalized in Shangqiu Hospital of Traditional Chinese Medicine for surgical treatment were enrolled from June 2009 to June 2015. Osteosarcoma and adjacent tissues（>5 cm from tumors） were collected. The expressions of ZFAS1 were determined by real-time fluorescence quantitative polymerase chain reaction（RT-qPCR）. All the patients were followed up for 5 years until June 30，2020. The survival time of the patients were recorded. Kaplan-Meier method was used for survival analysis，and Cox regression model was used for prognostic influencing factor analysis. Results The relative expression level of ZFAS1 in osteosarcoma tissues was 2.74±0.23，which was higher than 1.01±0.09 in adjacent tissues（t=71.876，P<0.001）. The relative expression levels of ZFAS1 in osteosarcoma tissues of patients with different Enneking stages，KPS scores，degrees of differentiation and metastasis had statistical significance（P<0.05）. Kaplan-Meier survival analysis results showed that the survival time of patients in low expression group was（46.24±2.55） months，and the 5-year survival rate was 61.11%，which were higher than those in high expression group，which were（26.09±2.76） months and 21.28%，respectively（Log-rank χ²=22.059，P<0.001）. The results of Cox proportional hazard regression model showed that Enneking stage，the degree of differentiation，metastasis and ZFAS1 expression were independent risk factors affecting patients' prognosis [hazard ratios（HR）were 2.620，0.384，2.197 and 1.978，95% confidence intervals（CI）were 1.203-5.706，0.186-0.791，1.131-4.270 and 1.034-3.784]. Conclusions The expression of ZFAS1 in osteosarcoma tissues is related to the pathological indicators of malignant progression of patients and prognosis，which is an independent risk factor affecting the prognosis of patients.

Key words: Zine finger antisense 1, Osteosarcoma, Pathological indicator, Survival analysis, Influencing factor