The Experimental Study Of Id1 Expression In Bladder Transitional Cell Carcinoma Tissue And Exfoliated Urothelial Cells

Objective The family of inhibitor of differentiation/DNA binding (Id) proteins is known to positive regulate proliferation and negative regulate differentiation in several tissues. One member of this gene family, Idl, has been implicated over expression in certain tumors, such as mammary, esophageal , pancreatic and prostate. Transitional cell cancer (TCC) is over 90% in bladder tumor. It's high local recurrence rate is associated with TCC cell differentiation. There are few report dealing with expression of Idl in bladder transitional cell carcinoma(BTCC). Therefore, the research try to assess the precise significance of Idl in BTCC and normal bladder tissue and to explore the possibility of analysis Idl expression in exfoliated urothelial cells to diagnose BTCC.Material and methods: BTCC specimens were obtained from 111patients with different cell differentiation. A total of 12. normal bladder tissue specimens were used for comparison. Immunohistochemical study wasperformed using the polyclonal antibody against human Idl protein . To detect expression of Idl mRNA and protein , 30 BTCC and 10 nomal mucous membrane of bladder are analysed using RT-PCR and Western blot. To detect the Idl expression in exfoliated urothelial cells, cellular immunology and cytological examination were performed respectively in 58 BTCC samples and 20 nonmalignant disease samples.Result: Negative expression of Idl in most normal bladder tissue wasobserved in immunohistochemical study. In contrast, 87.38%BTCC showed significant positive Idl expression. The positive expression rate of Idl in G1,G2 and G3 BTCC was 88.89%,87.50% and 85.72% respectively. Idl mRNA was detected in 73.3% BTCC using RT-PCR analysis,while no Idl mRNA was found in normal bladder tissue. In Western Blot analysis , 20% normal bladder tissues showed positive Idl expression, while 83.3% BTCC showed positive Idl expression. The Idl expression was not related to the BTCC grades.In exfoliated urothelial cells study, the cytological examination sensitivity was 39.7 % and its specificity was 95 %. The sensitivity of Gl ,G2 and G3 tumor was 20 % ,35 % and 66.7 % respectively. The cellular immunology test's sensitivity was 91.4%,and its specificity was 65% when the diagnosis standard was found a positive Idl marked cell. But when the cut-off value was over 10% positive Idl marked cell,its sensitivity was 75.9 %, and its specificity was 90 %. The sensitivity of Gl ,G2 and G3 tumor was 70%,75% and 83.3% respectively. Its sensitivity was not related with tumor grades(P>0.05). The cellular immunology test have a higher sensitivity for BTCC compared with cytological examination(p<0.05).Conclusions: Our result showed that most BTCC was over expression ofIdl .Idl expression was not related to tumor grade but related to tumor stage. Idl may have important roles in the BTCC's development and recurrence. To detect Idl expression using cellular immunology have higher sensitivity compared to cytological examination in exfoliated urothelial cells for BTCC. Idl may be used as a marker of TCC for screening,diagnosis and follow-up.