Overexpression of BMI‐1 is associated with poor prognosis in cervical cancer

Abstract

It has been reported that BMI-1, a gene transcription promoter overexpressed in various human cancers, is associated with poor survival. We investigated whether BMI-1 is a marker for cervical cancer by detecting the expression of BMI-1 in cervical cancer. An immunohistochemistry (IHC) streptavidin-peroxidase technique was used to identify BMI-1 protein expression in 302 cervical cancer specimens. Reverse transcription polymerase chain reaction and Western blot were employed to measure BMI-1 mRNA and protein level. The correlation between BMI-1 expression and clinicopathological factors was analyzed. Both BMI-1 mRNA and protein expression were evident in cervical carcinoma tissues. An intense positive rate of 55.3% (167/302) was observed by IHC. High BMI-1 expression was correlated with clinical stage, lymph node metastasis, vascular invasion and human papillomavirus (HPV) infection (P < 0.05), but there is insufficient evidence to confirm its value in tumor size, age, estrogen or progesterone receptor (P > 0.05). The BMI-1 protein level was positively correlated with the clinical stages of cervical carcinoma and a high BMI-1 expression was associated with poor prognosis (P < 0.05). The high expression of BMI-1 in cervical cancer is related to tumor progression, lymph node metastasis and HPV infection, suggesting that cervical cancer with excessive BMI-1 expression possesses high metastases potential and that BMI-1 may be a promising biomarker for predicting metastasis in cervical cancer.