Clinicopathological and prognostic significance of the long non-coding RNA HOTAIR high expression in head and neck squamous cell carcinoma: a systematic review and meta-analysis

BACKGROUND: Long non-coding RNAs (lncRNAs) have been demonstrated to possess critical biological functions that regulate occurrence and progression of tumors. The HOX transcript antisense intergenic RNA (HOTAIR) is one of the most studied lncRNAs. This study was designed to investigate the association of HOTAIR expressions with clinicopathologic features and prognosis in head and neck squamous cell carcinoma (HNSCC). METHODS: The PubMed, Web of Science, Embase, Cochrane Library and SCOPUS databases were searched. The studies published before September 10, 2021 were screened. Two authors independently screened the literature and extracted data based on inclusion and exclusion criteria. Meta-analysis, bias assessment, sensitivity analysis and subgroup analysis were performed to improve accuracy and reliability. RESULTS: Seven studies comprising 546 patients were analysed to clarify the relationship between clinicopathologic features and HOTAIR expression, and six studies with 856 patients were applied to evaluate the effects of HOTAIR expressions on the prognosis. After removing those outliers through Galbraith plots and/or sensitivity analysis, the pooled results showed high HOTAIR expressions were associated with high T stage [odds ratio (OR) =2.32, 95% confidence interval (CI): 1.38–3.89, P=0.001], lymphnode metastasis (OR =2.71, 95% CI: 1.57–4.67, P=0.0003), high TNM stage (OR =3.92, 95% CI: 2.28–6.72, P<0.00001), poor histological grade (OR =2.21, 95% CI: 1.02–4.83, P=0.046), poor overall survival (OS) [hazard ratio (HR) =1.74, 95% CI: 1.19–2.56, P=0.005] and poor disease-free survival (DFS) (HR =1.64, 95% CI: 1.09–2.47, P=0.02). Subgroup analyses of T stage, lymphnode metastasis and histological grade identified possible heterogeneity sources, respectively ethnicity, cut-off, and detection methods. CONCLUSIONS: These findings suggest HOTAIR might serve as an excellent prognostic biomarker and predictor of clinicopathologic features in HNSCC.