Association of dynamic changes of methylated SFRP2 in ctDNA with prognosis in advanced gastric cancer.

Abstract

e15051 Background: Secreted frizzled-related protein 2 (SFRP2) is a tumor suppressor gene and its hyper methylation could cause its inactivation and promote cancer development. However, whether methylated SFRP2 (mSFRP2) in ctDNA could serve as prognostic biomarker for patients with gastric cancer has not been thoroughly studied. Methods: Stage III or IV gastric cancer patients treated with systemic chemotherapy in the Third Affiliated Hospital of Soochow University from 2015 to 2017 were included. The mSFRP2 before and during chemotherapy were dynamically detected from ctDNA by digital polymerase chain reaction-based technologies. Results: In total, 121 patients were enrolled, with 63 in stage III and 58 in stage IV. Baseline median mSFRP2 was higher in stage IV than stage III (64 VS 18 copies/ng, P < 0.001). In stage III GC, the top 50% mSFRP2 population had shorter median disease-free survival (DFS, 11.0 months VS NR; HR, 13.05; 95% CI, 3.05-55.95;) and overall survival (OS, 17.0 months VS NR; HR, 7.80; 95% CI, 1.81-33.60). Similar results were observed in stage IV GC that the median progression-free survival (PFS, 4.0 VS 7.0 months; HR, 2.74; 95% CI, 1.58-4.78) and OS (12.0 VS 16.0 months; HR, 3.14; 95% CI, 1.67-5.92) was shorter in patients with top 50% mSFRP2. During the dynamic monitor along treatment, elevated mSFPR2 was associated with worse PFS (5.0 VS 7.0 months; HR, 2.17; 95% CI, 1.25-3.76) and OS (12.0 VS 15.5 months; HR, 3.51; 95% CI, 1.94-6.35) in stage IV patients. Conclusions: Our study shows the association between SFRP2 methylation and its dynamic change and prognosis in patients with gastric cancer. Our results provide a potential biomarker in ctDNA for prognosis and dynamic monitoring in patients with gastric cancer.