We performed a prospectively planned evaluation of the potential biomarkers of the WNT/β-catenin pathway in phase II study in patients with metastatic renal cell carcinoma treated with everolimus. WNT/β-catenin component expression in tumor cells had no effect on survival; however, we found that the soluble E-cadherin level might interact with the response to everolimus therapy.Background:
The aim of the present study was to search for predictive and prognostic factors in patients with metastatic renal cell carcinoma (mRCC) treated with everolimus among the components of the WNT/β-catenin pathway.Patients and Methods:
In a prospective, single-arm, phase II study, patients with mRCC received everolimus (10 mg/d) in a 30-day cycle. We performed a prospectively planned evaluation of the potential biomarkers of the WNT/β-catenin pathway.Results:
The serum level of soluble E-cadherin (sE-cadherin) in patients with RCC was significantly greater than that in the controls (71.62 ± 22.28 pg/mL vs. 54.26 ± 10.317 pg/mL; P = .0069). After 2 cycles of everolimus therapy, we observed a significance increase in sE-cadherin (from 71.81 ± 21.18 pg/mL to 77.50 ± 28.212 pg/mL; P = .0151). The Dickkopf-1 protein levels in the study and control groups were not significantly different (P = .2135). The favorable independent predictors for everolimus therapy were normal lactate dehydrogenase level before treatment (hazard ratio [HR], 0.52; 95% confidence interval [CI], 0.28-0.98; P = .0443) and low sE-cadherin level (HR, 0.54; 95% CI, 0.29-0.98; P = .0422). On multivariate analysis, we observed that worse overall survival was seen in patients with a lower regression coefficient of sE-cadherin after 2 cycles of treatment (HR, 2.60; 95% CI, 1.23-5.52; P = .0128), an increased corrected calcium level (HR, 3.09; 95% CI, 1.21-7.88; P = .0180), and an increased lactate dehydrogenase level before treatment (HR, 1.98; 95% CI, 1.02-3.83; P = .0426).Conclusion:
WNT/β-catenin component expression in patients with mRCC had no effect on progression-free survival or overall survival. However, we found that the sE-cadherin level might interact with response to everolimus therapy, although confirmation in future studies is needed.