[Expression and clinical significance of Bmi-1 protein in bladder cancer].
OBJECTIVE
At present, the molecular mechanisms of development and progression of bladder cancer are still poorly understood. This study was to explore the expression and significance of Bmi-1 in bladder cancer, and analyze its correlations to clinicopathologic features and prognosis of bladder cancer.


METHODS
The expression of Bmi-1 protein in 137 specimens of bladder cancer and 30 specimens of normal bladder tissues was detected by SP immunohistochemistry, and its correlations to clinicopathologic features and prognosis of the patients were analyzed.


RESULTS
The positive rate of Bmi-1 protein was significantly higher in bladder cancer than in normal bladder tissues (54.3% vs. 16.7%, P<0.05). The positive rate of Bmi-1 protein was 20.6% in grade G1 bladder cancer, 54.3% in grade G2 bladder cancer, and 78.8% in grade G3 bladder cancer, with significant difference (P<0.05). It was significantly lower in superficial bladder cancer than in invasive bladder cancer (32.5% vs. 81.5%,P<0.05). The expression intensity of Bmi-1 was related to tumor size, classification, TNM stage and prognosis (P<0.05), but not to tumor number and tumor recurrence (P>0.05). The patients were followed up for 44-86 months, with a median of 66 months. The 5-year survival rate was significantly higher in superficial bladder cancer patients than in invasive bladder cancer patients (89.6% vs. 39.2%, P<0.05), and higher in Bmi-1-negative patients than in Bmi-1-positive patients (78.5% vs. 50.8%,P<0.05).


CONCLUSIONS
Bmi-1 protein is highly expressed in bladder cancer. Detecting Bmi-1 protein is helpful for diagnosis and prognostic evaluation of bladder cancer.
Qin
Zi-Ke
ZK
State Key Laboratory of Oncology in South China, Guangzhou, Guangdong, 510060, PR China. qinzike@263.net
Yang
Jian-An
JA
Zeng
Mu-Sheng
MS
Zhou
Fang-Jian
FJ
Han
Hui
H
Liu
Zhuo-Wei
ZW
Yu
Shao-Long
SL
Li
Yong-Hong
YH
Chen
Zhuang-Fei
ZF
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D009687:Nuclear Proteins / Q000378:metabolism*; D063150:Polycomb Repressive Complex 1; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*; D015996:Survival Rate; D047368:Tumor Burden; D001743:Urinary Bladder / Q000378:metabolism; D001749:Urinary Bladder Neoplasms / Q000378:metabolism* / Q000473:pathology; D055815:Young Adult
C069077:BMI1 protein, human; D014408:Biomarkers, Tumor; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; D063150:Polycomb Repressive Complex 1