BACKGROUND: Yes-associated protein 1 (YAP1) is an effector of the Hippo pathway, which is critical for regulating organ size and cell proliferation in mammals. To investigate the prognostic value of YAP1 in gastric cancer (GC), we assessed its expression in tumors from patients.
MATERIALS AND METHODS: We examined the nuclear expression of the YAP1 protein in 223 cases of GC, particularly of stage II and III disease, using immunohistochemistry.
RESULTS: Positive nuclear expression of YAP1 was detected in 27.4% (61/223) of total GCs, 29.1% (34/117) of the intestinal-type GCs (IGC) and 25.5% (27/106) of the diffuse-type GCs (DGC). In the IGC group, we found that the overall survival rate among patients with YAP1 nuclear expression-positive tumors was lower than that in the expression-negative group (p=0.021). Cox multivariate analysis revealed that the nuclear expression of YAP1 was an independent prognosticator of IGC (p=0.018).
CONCLUSION: The nuclear overexpression of YAP1 is an independent biomarker for poor survival, especially for patients with intestinal-type gastric cancer.