Abstract
Yes-associated protein 1 (YAP1), a downstream effector of the Hippo pathway, plays an important role in the development and progression of multiple malignancies, including human gastric cancer (GC). However, the clinical significance of YAP1 expression in GC needs to be comprehensively explored. Based on the pivotal role of YAP1 in the hippo pathway, we explored the clinicopathologic characteristics of YAP1 overexpression and its relationship to some tumor biomarkers in GC. Ninety cases of GC, chronic gastritis (CG) and CG with dysplasia samples were collected, and clinical data of all patients with GC were analyzed. The expression of YAP1 was assessed using immunohistochemical assay in biopsy samples. As a result, almost all the GC samples, but few CG and dysplasia samples showed YAP1 positive staining mainly in the nucleus. The expression of YAP1 was found in GC tissues with higher strong reactivity rate, compared with dysplasia and CG tissues (79.2% vs 47.1% and 15%, each p<0.001), and its expression level was elevated with the ascending order of GC malignancy. However, no significant correlation was found between the expression of YAP1 and epidermal growth factor receptor (EGFR) with gender, age, gross stage, degree of differentiation, tumor size, TNM staging, perineural infiltration, vascular invasion, lymphatic vessel invasion and lymph node metastases in patients with GC (each P>0.05). Furthermore, Spearman rank correlation analysis also showed no correlation of YAP1 with EGFR, Ki-67, CD34 and topoisomerase II (TOP II). Taken together, YAP1 is highly expressed in GC tissues compared with the dysplasia and CG tissues and its expression level is elevated with the ascending order of tumor malignancy; but, YAP1 expression does not correlate with the clinicopathologic characteristics and the expression of EGFR, Ki-67, CD34 and TOP II in GC.