Study On Expression Of DNMT1 In Transitional Cell Carcinoma Of Bladder By Real-time PCR And Its Clinical Significance

Objective To investigate expression of DNA methyltransferase 1 (DNMT1) mRNA in tissue of human transitional cell carcinoma of bladder (TCCB), and analyze its relevance with grade, stage, and other clinical parameters in TCCB.Methods DNMT1 mRNA expression was measured by real-time PCR in tumor tissue and assessed for its potential clinical relevance.Specimens from 35 patients with TCCB were analyzed, the controls being normal bladder tissues (n=10).Results Higher levels of expression of DNMT1 transcripts were detected in tumor (3.253±0.736) than in normal tissues (1.526±0.441, P<0.001). Respectively, expression level of DNMT1 mRNA in stage Tis-T1, T2-T4 was 3.135±0.667, 3.308±0.841; in grade I, II, III was 3.125±0.586, 3.245±0.643, 3.433±0.554; in elder (>40 y)and nonelder (<40 y) group was 3.335±0.496, 3.012±0.269; in male and female group was 3.314±0.423, 3.008±0.203; in primary and recurrence group was 3.205±0.625, 3.447±0.334. mRNA levels did not correlate with grade, stage and recurrence (P>0.05); Higher levels of expression were associated with advanced age (P<0.05); Male group had significant higher levels of expression than female group (P<0.05).Conclusion Our study showes that DNMT mRNA is significantly up-regulated in TCCB than in normal bladder tissues. Therefore, CpG hypermethylation of promoter region is up-regulated and consequently, anti-oncogene is inactivated. Different levels of expression of DNMT1 mRNA in man and woman may play a important role in the mechanism that male have a much higher morbidity of TCCB than female. Up-regulation of DNMT1 mRNA with age may answer the question why TCCB is mostly seen in older people.