| Background and purpose: Bladder carcinoma is the most common cancer of genitourinary tract, over 90% of bladder cancers are of transitional cell origin. Recurrence of transitional cell carcinoma of the bladder is high. More than 50 to 70% of superficial tumors recur within 5 years and almost 90% recur within 15 years while about 30% progress to invasive disease. Thus, early detection and monitoring of patients with transitional cell carcinoma of bladder may be important for successful treatment. But it still can't be clearly understood for the pathogenesis and the carcinogenesis mechanism of bladder carcinoma, so there isn't diagnostic test that is less invasive than cystoscopy but more sensitive than cytology. As many cancers, cell proliferation factors play an important role in the carcinogenesis and development of transitional cell carcinoma of bladder. Minichromosome maintenance 5 (MCM5) is a new cell proliferation factor, which can be used as a marker of bladder cancer.In the present study, we tested the expression of MCM5 in bladder carcinoma tissues and urine exfoliated cells, to evaluate the value of diagnosis of bladder carcinoma by detection of MCM5 in urine sediments.Objects and methods: 76 samples of bladder carcinoma tissue with histopathologis evidence of transitional cell carcinoma and 20 samples of normal bladder tissue were tested for MCM5 by immunohistochemical technique (S-P). 36 of these bladder carcmoma tissue samples (6 cases of G1, 16 of G2 and 14 of G3; 19 cases of Tis-T1 and 17 of T2-T4) and 10 of these normal bladder tissue samples were surgically resected fresh samples comed fromthe first affiliated hospital of Zhengzhou university, the expressions of MCM5 mRNA in which were examined by RT-PCR, too. Other 40 bladder carcinoma tissue samples (15 cases of G1, 14 of G2 and 11 of G3; 27 cases of Tis-T1 and 13 of T2-T4) and 10 normal bladder tissue samples were paraffin-embedded samples kept in the archives, which were collected at Henan province people's hospital.131 urine samples comed from the first affiliated hospital of Zhengzhou university were classified into 3 groups: group 1 patients had a mean age of 60.9 with diagnosis of bladder transitional cell carcinoma (were diagnosed based on previous cystoscopy and confirmed by histopathology) (n=72), Which included 55 cases of primary bladder carcinomas and 17 cases of recurrent bladder carcinomas; 27 cases of G1, 28 of G2 and 17 of G3; 49 cases of Tis-T1 and 23 of T2-T4; group 2 patients had a mean age of 54.2 with diagnosis of other urological diseases, such as urinary tract infection, neurogenic bladder, benign prostatic hyperplasia (BPH), bladder polypus, renal cyst and urinary stones (n=49); and group 3 included healthy volunteers with mean age of 57.1 (n=10). The expressions of MCM5 in these urine samples were tested by RT-PCR. At the same time, all of these samples were submitted for cytology.Results: 1, Result of immunohistoehemic showed that MCM5 positive staining was located in nucleus. In normal bladder tissues, MCM5 expression was present only in basal epithelial cells, together with some cells in the immediate suprabasal several layers, the more superficial differentiating cells of each epithelium were negative. In transitional cell carcinoma of bladder tissues, in contrast, MCM5 was expressed in the majority of cells, extending to surface layers of stratified epithelia. The median labeling indexes (LI) of MCM5 were 65% in transitional cell carcinoma of bladder tissues and 17.5% in normal bladder tissues respectively (p<0.01). MCM5 protein expression was related to pathological grades and clinical stages. The median LI of MCM5 in grades 1, 2 and 3 were 38%, 62.5% and 84% respectively. Statistical significance was found in G1 and G2, G1 and G3, G2 and G3 respectively (p<0.01), The median LI of MCM5 in superficial and invasive tumor were 42.5% and 80% respectively. The difference of which was significant (p<0.01). MCM5/ β -actin (0.7900 ± 0.1903) and MCM5 mRNA positive rate (100%) in transitional cell carcinoma of bladder tissues were both significantly higher than those in nonnal bladdertissues (0.1967±0.1394, 60%). MCM5 mRNA expression was related to pathological grades and clinical stages (p<0.01). The result of RT-PCR was consistent with that of immunohistochemistry.2. The expression of MCM5 in tissues of bladder cancer was correlated with that in urine samples. The positive expression rate of MCM5 in bladder tissues by RT-PCR was 100%, which was not significantly different from that in urine samples (87.5%, p>0.05).3. The positive expression rate of MCM5 in urine samples from patients with transitional cell carcinoma of bladder was 87.5% (63/72), which was significantly higher than that in urine samples from patients with other urological diseases and healthy volunteers (6.1%, p<0.01). The positive rate of MCM5 in urine samples from patients with transitional cell carcinoma of bladder had no correlation with the pathological grades and clinical stages. But MCM5/β-actin was related to pathological grades and clinical stages (p<0.01). The positive rates of MCM5 in primary and recurrent bladder carcinomas were 87.3% and 88.2% respectively, the difference of which was not significant (p>0.05). MCM5/β -actin in primary and recurrent bladder carcinomas were 0.5354 ±0. 2748 and 0.5647 ± 0.2629 respectively, the difference of which was not significant too (p>0.05). The sensitivities of MCM5 and cytology to detect transitional cell carcinoma of bladder were 87.5% and 41.7%, reapectively. The former was significantly higher than the latter (p<0.01). The specificities of MCM5 and cytology to detect transitional cell carcinoma of bladder were 95% and 100%, reapectively. The: difference of them was not significant (p>0.05).Conclusion: The above results suggest that in normal bladder tissues, MCM5 expression was present only in basal epithelial cells, in transitional cell carcinoma of bladder tissues, in contrast, MCM5 was expressed in the majority of cells, extending to surface layers of stratified epithelia; MCM5-LI and MCM5/β -actin were correlated with pathological grades and clinical stages. Based on these we could draw a conclude that the over expression of MCM5 might be a key mechanisms in the carcinogeniesis of transitional cell carcinoma of bladder. The test of MCM5 in membrane cell could diagnose transitional cell carcinoma of bladder and forecast its malignancy.The expression of MCM5 in tissues of bladder cancer was correlated with that in urine samples, which indicated the expression of MCM5 in urine samples could reflect that intissues.The detection of MCM5 in urine sediments is sensitive, specific and non-invasive diagnostic tests for bladder cancer, could be used to diagnose primary and recurrent bladder carcinomas and forecast the prognosis of tumors. It is better than urinary cytology, and can reduce or replace the application of cystoscopy. |
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