Elevated expression of yes‑associated protein is associated with the malignant status and prognosis of laryngeal squamous cell carcinoma

Previous studies have demonstrated that elevated yes‑associated protein (YAP) expression is associated with tumor aggression and poor prognosis in various types of human cancer. However, the clinicopathological significance and the prognostic value of YAP in laryngeal squamous cell carcinoma (LSCC) is unknown. The aim of the present study was to identify the expression pattern and prognostic significance of YAP in patients with LSCC. YAP mRNA and protein expression levels were examined in fresh and archived LSCC samples using the reverse transcription‑quantitative polymerase chain reaction, immunohistochemistry (IHC) and western blotting. The association between YAP expression levels with the malignant status and prognosis of patients with LSCC was analyzed. Upregulated protein and mRNA expression levels of YAP were detected in LSCC tissues compared with paired healthy surgical margin tissues. Positive expression of YAP was identified in 84/121 (69.4%) LSCC tissues and in 4/30 (13.3%) healthy surgical margin tissues by IHC. Positive YAP protein expression was significantly associated with clinical stage, TNM classification, lymph node metastasis and differentiated degree. Patients with positive YAP expression exhibited a significantly decreased overall survival time compared with patients with negative YAP expression (P=0.0002). Multivariate analysis indicated that the level of YAP expression was an independent prognostic factor for poor survival in patients with LSCC (P=0.012). In conclusion, the expression level of YAP was significantly increased in LSCC and associated with the malignant status of LSCC. Therefore, YAP may represent a novel biomarker for predicting the prognosis of patients with LSCC.