Prognostic significance of nuclear Yes-associated protein 1 in patients with nonsmall cell lung cancer: A systematic review and meta-analysis

BACKGROUND: Nuclear Yes-associated protein 1 (YAP1) has often been regarded as an adverse prognostic indicator in various tumors. Recent studies have associated YAP1 with unfavorable prognosis in nonsmall cell lung cancer (NSCLC). However, due to small sample sizes, the prognostic value of nuclear YAP1 in NSCLC patients is not well understood. In the present study, we evaluated the prognostic role of nuclear YAP1 in NSCLC patients via a systematic review and meta-analysis. METHODS: We searched the PubMed, EMBASE, Cochrane, Web of Science, China National Knowledge Infrastructure (CNKI), and Wanfang Databases for papers investigating the prognostic significance of nuclear YAP1 expression in NSCLC patients. Hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) were calculated with reference to overall survival (OS) and progression-free survival (PFS) of NSCLC patients to provide synthesized estimates of the effects of nuclear YAP1 expression. RESULTS: Among 414 cases, higher nuclear YAP1 expression presented as a predictive factor of poorer OS (HR = 1.52; 95% CI: 1.11–2.08; P = .01; I(2) = 0.0%) and decreased PFS (HR = 2.11; 95% CI: 1.52–2.93; P < .001; I(2) = 44.2%) in NSCLC patients. Subgroup analysis revealed shortened OS (HR = 1.63; 95% CI: 1.14–2.34; P = .007; I(2) = 0.0%) and worse PFS (HR = 2.25; 95% CI: 1.53–3.30; P < .001; I(2) = 0.0%) in patients from Asia with higher nuclear YAP1 expression. Prognosis was also worse in patients with III–IV stage cancer (PFSHR = 2.09; 95% CI: 1.45–3.01; P < .001; I(2) = 58.1%) and in patients treated with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) (OS HR = 1.59; 95% CI: 1.00–2.51; P = .048; I(2) = 15.5%, and PFS HR = 2.35, 95% CI: 1.62–3.42; P < .001; I(2) = 0.0%). CONCLUSION: High expression of nuclear YAP1 was associated with shorter survival outcome in patients with NSCLC.