Abnormally expressed long non-coding RNAs in prognosis of Osteosarcoma: A systematic review and meta-analysis

BACKGROUND: Numerous studies have reported the relationship between Long non-coding RNAs (LncRNAs) expression and prognosis of osteosarcoma, but less consensus has been reached. Our meta-analysis was conducted to quantitatively assess the relationship between the expression of LncRNAs, prognosis and clinical pathology in osteosarcoma development. METHODS: PubMed,Embase,Web of Science,The Cochrane Library,SionMed,CNKI and WanFang databases were carefully searched to identify eligible studies. The pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to evaluate the prognostic significance of LncRNAs expression in osteosarcoma. Moreover, meta-regression analysis and subgroup analysis were carried out to explore the potential sources of heterogeneity. RESULTS: A total of 20 studies comprising 1749 patients were included in present meta-analysis. The results showed that the over-expression of LncRNA had a significant correlation with overall survival (OS) (HR = 2.16, 95% CI:1.68–2.79), and was not related to disease free survival (DFS) (HR = 0.71, 95% CI:0.05–9.53). Subgroup analysis further indicated that LncRNA transcription level was significantly associated with alkaline phosphatase (HR = 2.13, 95% CI:1.58–2.88) , tumor size (< 8/ ≥ 8:HR = 1.97, 95% CI: 1.55–2.62) , metastasis (yes/no: HR = 2.14,95% CI:1.15–3.97) , distant metastasis(presence/absence: HR = 4.02, 95% CI:3.05–5.23) and Enneking stage(IIA /IIB-III:HR = 3.2, 95% CI:2.48–4.14), but not associated with age (≤ 25/ > 25:HR = 1.01, 95% CI:0.78–1.3), gender(female/male: HR = 1.15, 95% CI: 0.96–1.37), tumor site (femur,tibia/elsewhere:HR = 1.15, 95% CI:0.94–1.4) and chemotherapy (yes/no: HR = 1.45, 95% CI:0.46–4.63). CONCLUSIONS: This study demonstrated that abnormal LncRNAs expression might be potential prognostic markers to predict worse overall survival in osteosarcoma patients. However, the cut-off values may be the source of heterogeneity.