Expression level of Bmi-1 oncoprotein is associated with progression and prognosis in colon cancer.
OBJECTIVE
To investigate the clinicopathologic significance and predictive value of Bmi-1 expression in patients with colon cancer.


METHODS
Bmi-1 expression was assessed by immunohistochemistry, PCR, and western blotting in specimens from 203 patients and by immunohistochemistry in 66 specimens of lymph node metastasis (LNM).


RESULTS
Positive staining of Bmi-1 occurred in 7.9% (16/203), 66.5% (135/203), and 86.4% (57/66) of specimens from normal tissue, colon cancer, and LNM, respectively. Staining was significantly correlated with clinical stage, depth of invasion, nodal involvement, distant metastasis, and Ki67 level. Bmi-1 was upregulated at the transcriptional and translational levels. Patients with Bmi-1-positive localized tumors had a much lower 5-year disease-free survival (relative risk 2.919, P < 0.0001) and overall survival (relative risk 5.056, P < 0.0001). Bmi-1 immunoreactivity emerged as an independent prognostic factor in the multivariate analysis.


CONCLUSIONS
We have shown that expression of Bmi-1 was elevated in colon cancer and might serve as an independent prognostic marker.
Li
Da-wei
DW
Department of General Surgery, Shanghai Jiaotong University Affiliated with First People's Hospital, Shanghai, People's Republic of China.
Tang
Hua-mei
HM
Fan
Jun-wei
JW
Yan
Dong-wang
DW
Zhou
Chong-zhi
CZ
Li
Shu-xia
SX
Wang
Xiao-liang
XL
Peng
Zhi-hai
ZH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000096:biosynthesis / Q000235:genetics; D015153:Blotting, Western; D003110:Colonic Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009687:Nuclear Proteins / Q000096:biosynthesis* / Q000235:genetics; D063150:Polycomb Repressive Complex 1; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis* / Q000235:genetics; D012008:Recurrence; D012097:Repressor Proteins / Q000096:biosynthesis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016019:Survival Analysis; 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