Expression Of Bmi-1 And P16 Gene In Transitional Cell Carcinoma Of Bladder And Their Correlation

Objective To detect the expression of Bmi-1 and P16 gene in transitionnal cell of bladder(TCC), explore their clinical significance, and reveal the effect and relation of their expression.Methods The fresh carcinoma tissues of 61 patients with TCC and 12 normal bladder tissues from June 2006 to september 2008 were detected the relative amount of Bmi-1 and P16 mRNA by real-time quantitative reverse transcription polymerase chain reaction (RT-PCR). The patient group could be divided into two subgroups according to the world Health Organization of pathologic grades in 2004: High grade (32 cases), Low grade (29 cases), and two subgroups according to the TNM classification of malignant tumors: Tis～T1 grades(45 cases), T2～T4 grades(16 cases). Otherwise, there were 49 cases who occurred tumor at first time and 12 cases who recurred tumor according to the clinical data of 61 patients.Results The relative expression of Bmi-1 and P16 gene were 0.031±0.011 and 0.165±0.030 in normal bladder tissues. In TCC, the relative expression of Bmi-1 and P16 gene were 0.242±0.129 and 0.059±0.021. The Bmi-1 and P16 expression level were statistically significant compared with the control group (P<0.01). Different expression levels of Bmi-1 mRNA could be observed among different pathologic grades, low grade: 0.157±0.051, and high grade: 0.335±0.125. The differences in pathological grades were statistically significant (P<0.01). The expression of Bmi-1 mRNA also differed between different clinical stages, T_is～T₁ grades: 0.215±0.113,T₂～T₄ grades: 0.316±0.147 (P<0.01). The expression of Bmi-1 mRNA was well relation with the pathologic grades and clinical stages (P<0.01). The expression levels of P16 mRNA was: low grade: 0.074±0.017, and high grade: 0.043±0.012; T_is～T₁ stages: 0.064±0.023, T₂～T₄ stages: 0.048±0.013. The differences between pathologic grades and clinical stages were statistically significant (P<0.05). According to the clinical data, there were 49 cases who occurred tumor at first time and 12 cases who recurred tumor. The relative expression of Bmi-1 mRNA in recurrence group was 0.347±0.116, and was higher than other 49 cases who occurred tumor at first time (P<0.01). Otherwise, the relative expression of P16 mRNA in recurrence group was 0.051±0.024, and lower than other 49 cases who occurred tumor at first time.Nevertheless, there were not statistically significant (P>0.05). We found there was a tendency that the higher expression of Bmi-1, the lower expression of P16. It was also found that the expression of Bmi-1 was negativity relation with the expression of P16 with Spearman correlation analysis (rs=-0.686, P<0.05).Conclusion 1.The relative expression of Bmi-1 in TCC was higher than the control group, while the relative expression of P16 in TCC was lower than the control group.The tumor over-express Bmi-1 and low-express P16 maybe have a close relation with the oncogenesis of bladder cancer. 2. The expression of Bmi-1 and P16 was highly related to pathologic grades and clinical stages. The more expression of Bmi-1 and (or) less expression of P16, the worse clinical-pathologic features and higher invasion. 3. The relative expression of Bmi-1 mRNA in recurrence group was higher than these patients who occurred tumor at first time. It suggested that patients who were the more expression of Bmi-1 were more easy to recur. Bmi-1 may have something value of suggesting tumor recurrence. 4. There was a tendency that the higher expression of Bmi-1, the lower expression of P16 (rs=-0.686, P<0.05). Bmi-1 may deregulate the expression of P16 by P16ink4a/cyclinD/Rb, and then lead to the oncogenesis and development of bladder cancer. .