CALN1 Hypomethylation As A Biomarker For High-Risk Bladder Cancer

Abstract Background: DNA methylation in cancer is considered a diagnostic and predictive biomarker. We investigated the usefulness of the methylation status of CALN1 as a biomarker for bladder cancer using methylation-sensitive restriction enzyme (MSRE)-quantitative polymerase chain reaction (qPCR).Methods: A total of 82 bladder cancer fresh samples were collected via transurethral resection of bladder tumors. Genomic DNA was extracted from samples, and MSRE-qPCR was performed to determine the CALN1 methylation percentage. Reverse transcription-qPCR was performed to assess the correlation between CALN1 methylation and mRNA expression. The association between CALN1 methylation percentage and clinicopathological variables of all cases and intravesical recurrence of non-muscle-invasive bladder cancer (non-MIBC) cases were analyzed.Results: Of the 82 cases, nine were MIBC cases and 71 were non-MIBC cases that had not undergone total cystectomy. The median CALN1 methylation percentage was 79.5% (interquartile range: 51.1, 92.6). CALN1 gene methylation percentage had a negative relationship with CALN1 mRNA expression (Spearman’s ρ = -0.563 and P = 0.0121). Hypomethylation of CALN1 was associated with advanced tumor stage (P = 0.0007) and histologically high grade (P = 0.0178). Furthermore, multivariate analysis revealed that CALN1 hypomethylation was an independent risk factor for intravesical recurrence in non-MIBC patients (hazard ratio 3.83, 95% confidence interval; 1.14–13.0, P = 0.0305). Conclusion: Our findings suggest that CALN1 methylation percentage could be a useful molecular biomarker in bladder cancer patients.