Abstract: Objective To investigate the expression of Dickkopf-related protein 2(DKK2) in cancer tissues of patients with bladder cancer and its relationship with prognosis. Methods Eighty-six patients with bladder cancer who were treated in our hospital from May 2016 to June 2018 were selected for surgical treatment of bladder cancer,and bladder cancer tissue specimens and adjacent tissues(≥5 cm from the cancer tissue) were collected.Compare the expression of DKK2 in cancerous tissues and adjacent tissues.Analyze the relationship between DKK2 expression in cancer tissues and clinicopathological characteristics.Cox regression analysis of multiple factors affecting the prognosis of bladder cancer patients.To analyze the relationship between the expression of DKK2 in cancer tissues and the prognosis of bladder cancer patients. Results The negative expression rate of DKK2 in bladder cancer tissue was higher than that in adjacent tissues( P <0.05).There was no significant difference in the negative expression rate of DKK2 in cancer tissues of bladder cancer patients with different gender,age,BMI,smoking,drinking,and the number of tumors( P >0.05).The maximum diameter of the tumor was ≥3 cm,the clinical stage Ⅲ to Ⅳ,there was The negative expression rate of DKK2 in the cancer tissues of patients with lymph node metastasis,poorly differentiated,and vascular invasion of bladder cancer is higher than that in patients with tumors with a maximum diameter of <3 cm,clinical stages Ⅰ to Ⅱ,no lymph node metastasis,moderate/well differentiated,and no vascular invasion.The difference was statistically significant( P <0.05).86 patients with bladder cancer were followed up for 3 years,and 5 cases were lost to follow-up.Of the remaining 81 patients,19 died,with a mortality rate of 23.46%.Cox regression analysis showed that clinical stage,lymph node metastasis,degree of differentiation,and negative expression rate of DKK2 were independent factors affecting the prognosis of bladder cancer patients(OR=3.018,2.267,3.184,4.645, P <0.05).By the end of the follow-up,the survival rates of patients with DKK2-positive and DKK2-negative bladder cancer were 94.44% and 71.43%,respectively.The survival curve of patients with positive expression of DKK2 and patients with negative expression of DKK2 were compared,and the difference was statistically significant( P <0.05). Conclusion The negative expression rate of DKK2 in cyst carcinoma tissues is relatively high.The expression of DKK2 has a certain correlation with tumor diameter,clinical stage,lymph node metastasis,degree of differentiation,vascular invasion and prognosis in patients with bladder cancer.Monitoring its expression is beneficial to patients with bladder cancer Prognosis evaluation has important reference value.

Key words: bladder cancer, cancer tissue, Dickkopf-related protein 2, prognosis