Abstract:

Background and purpose: Accumulation of genetic and epigenetic changes that lead to the activation of proto-oncogenes or inactivation of tumor suppressor genes play important roles in development and progression of bladder cancer. We aimed to investigate the methylation patterns of TWIST1 gene in bladder cancer. Methods: A total number of 78 histologically confirmed bladder tumor samples and paired 75 urine samples constituted the study group and was compared with 75 age-matched and gender-matched non-cancerous individuals. DNA was purified from both tumor, adjacent tissues and urine samples. The methylation status of the TWIST1 gene was analyzed by methylation-specific polymerase chain reaction (MSP) in both urinary bladder cell carcinoma samples, adjacent tissues and urine samples. Sensitivity and specificity values of the method were assessed and compared with the results of the cytology test. Results: Methylation of TWIST1 was detected in 88.5% of carcinoma samples and 84% of the paired urine samples，respectively; 11.5% carcinoma adjacent tissues and 5.3% control urine sample was methylated. The sensitivity by urine cytology detection method was 49.3% in in bladder cancer patients, and was 17.3% in control group. The sensitivity of TWIST1 genes was 66.7% for low-grade cases. The sensitivity of urine cytology was 33.3% for the same low-grade cases. Conclusion: The methylation analysis of TWIST1 gene may be a simple, non-invasive, sensitive, and specific method for early detecting bladder cancer cells in urine.

Key words: TWIST1, Bladder tumor, Cytology test, Methylation