The effect of YAP expression in tumor cells and tumor stroma on the prognosis of patients with squamous cell carcinoma of the oral cavity floor and oral surface of the tongue

Classic prognostic factors, such as clinical advancement of the disease and histological grade of the tumor, continue to have a decisive role in the selection of therapeutic strategy in patients with carcinoma of the oral cavity floor and oral surface of the tongue (OCC). YAP1/Yes-associated protein 1 (YAP) and transcriptional co-activator with PDZ-binding motif, WWTR1 (TAZ) proteins, appear to be promising markers that may be used to develop personalized therapies. The aim of the present study was to analyze the associations between the levels of YAP, TAZ and tyrosine-protein phosphatase non-receptor type 14 (PTPN14) and to determine whether the increased expression of YAP and TAZ had an effect on tumor cell proliferation, as determined by minichromosome maintenance 7, DNA replication licensing factor 7 expression. Their prognostic value was also assessed. In total, 127 patients who underwent radical surgery and were subjected to adjuvant radiation therapy due to squamous cell OCC were enrolled in the present study. The results demonstrated an evident effect as YAP expression increased in cancer-associated fibroblasts, which induced unfavorable prognosis in patients. In addition, a positive association between proliferation in cancer cells and YAP expression in stromal cells was observed. A lack of YAP expression in the cytoplasm of tumor cells was a factor for poor prognosis with regard to disease-free survival and disease specific survival. No statistically significant correlations between YAP and TAZ expression and PTPN14 expression were identified, nor was a correlation between cell proliferation and the presence of YAP and TAZ in tumor cells observed. The results indicated that YAP expression levels may support the development of personalized therapies for patients.