Expression And Significance Of YAP And Its Phosphorylated Form In Osteosarcoma

Background and purpose:Osteosarcoma is a primary malignant bone tumor that occurs in children and adolescents.The incidence rate is low but the prognosis is very poor.The 5-year survival rate of patients with lung metastasis is only 20%-30%.At present,the main treatment mode of osteosarcoma is still preoperative neoadjuvant chemotherapy +surgery + postoperative chemotherapy.The lack of effective specific targeted drugs makes the treatment of osteosarcoma enter a bottleneck period.Therefore,in this study,immunohistochemistry was used to detect whether there is differential expression of Yes-associated protein(YAP)and its phosphorylated form(p-YAP)in osteosarcoma tissues and normal bone tissues of the control group,and the chi-square test was used to analyze whether the differential expression was statistically significant and whether the two were correlated with the clinicopathological factors of the patients.To explore the role of YAP phosphorylation in the development of osteosarcoma,and to prepare for the further study of the molecular mechanism of YAP in the development of osteosarcoma through cell experiments.Methods:In this study,the expression of YAP and its pYAP in 33 cases of osteosarcoma tissues a nd 9 cases of normal bone tissues was detected by two-step immunohistochemical method.Chi-square test was used to analyze whether there was statistical significance in the differential expression of the two in osteosarcoma and normal bone tissue,as well as the correlation between the two and the clinicopathological characteristics of patients.At the same time,all patients included in the experiment were followed up,and survival analysis of clinicopathological characteristics was conducted.Result:1.The positive rate of YAP was 75.8% in osteosarcoma tissues and 11.1% in normal bone tissues.The difference was statistically significant(z = 9.904,P = 0.001).2.The positive rate of p-YAP in osteosarcoma tissues was 36.4%,and the expression of p-YAP in high-grade osteosarcoma tissues was significantly lower than that in low-grade tumor tissues(z=5.144,p=0.012).3.The expression level of YAP had statistical significance with lung metastasis,expression of alkaline phosphatase and lactate dehydrogenase,but had no statistical significance with gender,age,location of disease,pathological fracture,Enneking stage,KPS score and malignant degree of tumor.4.The expression of p-YAP was significantly correlated with lung metastasis,lactate dehydrogenase,malignant degree of tumor and Enneking stage,but not with gender,age,location of disease,pathological fracture,KPS score and alkaline phosphatase.5.In the survival analysis,YAP,p-YAP,site of disease,lung metastasis,lactate dehydrogenase,Enneking stage were related to the survival status of patients.Conclusions.1.Compared with normal bone tissue,the expression of YAP in osteosarcoma is significantly increased,and its expression is statistically significant with lung metastasis,alkaline phosphatase and lactate dehydrogenase,and is negatively correlated with the survival status of patients,which may play a role in promoting cancer in osteosarcoma.2.The expression of p-YAP was statistically significant to the lactate dehydrogenase of tumor tissue,lung metastasis,malignant degree of tumor and Enneking stage,and was positively correlated with the survival status of patients.Moreover,the expression of p-YAP in low-grade osteosarcoma was significantly higher than that in high-grade osteosarcoma,which may play a role in tumor suppression during the progression of osteosarcoma.