Core Promoter Methylation in Pretreatment Cell-Free DNA: A Liquid Biopsy Tool for Muscle-Invasive Bladder Cancer Treatment Outcome.

PURPOSE

The lack of personalized management of bladder cancer (BlCa) results in patients' lifelong post-treatment monitoring with invasive interventions, underlying the urgent need for tailored and minimally invasive health care services. On the basis of our previous findings on miR-143/145 cluster methylation in bladder tumors, we evaluated its clinical significance in pretreatment cell-free DNA (cfDNA) of patients with BlCa.

MATERIALS AND METHODS

Methylation analysis was performed in our screening cohort (120 patients with BlCa; 20 age-matched healthy donors) by bisulfite-based pyrosequencing. Tumor recurrence/progression for patients with non-muscle-invasive bladder cancer, and progression and mortality for patients with muscle-invasive bladder cancer (MIBC) were used as clinical end point events in survival analysis. Bootstrap analysis was applied for internal validation of Cox regression models and decision curve analysis for assessment of clinical benefit on disease prognosis.

RESULTS

Decreased methylation of core promoter in pretreatment cfDNA was associated with short-term disease progression (multivariate Cox: hazard ratio [HR], 2.027 [95% CI, 1.157 to 3.551]; = .010) and poor overall survival (multivariate Cox: HR, 2.098 [95% CI, 1.154 to 3.817]; = .009) of patients with MIBC after radical cystectomy (RC). Multivariate models incorporating promoter methylation in cfDNA with tumor stage clearly ameliorated patients' risk stratification, highlighting superior clinical benefit in MIBC prognostication.

CONCLUSION

Reduced pretreatment cfDNA methylation of core promoter was markedly correlated with increased risk for short-term progression and worse survival of patients with MIBC after RC and adjuvant therapy, supporting modern personalized and minimally invasive prognosis. Methylation profiling of core promoter in pretreatment cfDNA could serve as a minimally invasive and independent predictor of MIBC treatment outcome and emerge as a promising marker for blood-based test in BlCa.