title: Direct serum assay for cell-free bmi-1 mRNA and its potential diagnostic and prognostic value for colorectal cancer.
abstract: OBJECTIVE
  Cell-free Bmi-1 mRNA is stably detectable in the serum/plasma and is associated with the development and progression of some tumors. Previous methods detecting extracellular Bmi-1 mRNA with RNA extraction are inefficient. This study developed a novel reverse transcription quantitative PCR (RT-qPCR) approach directly applied in serum (RT-qPCR-D) to quantify Bmi-1 mRNA, and assessed its diagnostic and prognostic potential in colorectal cancer.
  
  
  METHODS
  The feasibility of the RT-qPCR-D method was first analyzed in 50 serum samples. Then, using the RT-qPCR-D method, Bmi-1 mRNA expression was validated in serum from an independent cohort of patients with 87 normal colonoscopy, 76 hyperplastic polyp, 82 inflammatory bowel disease, 68 adenoma, and 158 colorectal cancer. Receiver operating characteristic (ROC) curves and Cox analyses were used to evaluate its diagnosis and prognosis value, respectively.
  
  
  RESULTS
  In a pilot study, levels of Bmi-1 mRNA were increased in colorectal cancer serum samples detected by RT-qPCR-D and significantly associated with results obtained by RT-qPCR. In a validation cohort, serum Bmi-1 mRNA levels were significantly elevated in the colorectal cancer group and the adenoma group when compared with other groups. The area under ROC curve distinguishing colorectal cancer from benign colorectal diseases was 0.888, with 72.2% sensitivity and 94.9% specificity, which was superior to carcinoembryogenic antigen. Bmi-1 mRNA levels were significantly associated with survival. Cox analysis indicated Bmi-1 mRNA was an independent prognostic factor for overall survival.
  
  
  CONCLUSIONS
  Detection of cell-free Bmi-1 mRNA in serum by RT-qPCR-D is a simple and noninvasive approach and may be used for colorectal cancer diagnosis and prognosis.
authors.affiliation: Department of Clinical Laboratory, Qilu Hospital, Shandong University, Jinan, Shandong Province, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Gastroenterology, Qilu Hospital, Shandong University, Jinan, Shandong Province, China.
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Clinical Laboratory, Traffic Hospital of Shandong Province, Jinan, Shandong Province, China.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Clinical Laboratory, Traffic Hospital of Shandong Province, Jinan, Shandong Province, China.
authors.forename: Xinfeng
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Clinical Laboratory, Qilu Hospital, Shandong University, Jinan, Shandong Province, China.
authors.forename: Guixi
authors.initials: G
authors.lastname: Zheng
authors.affiliation: Department of Clinical Laboratory, Qilu Hospital, Shandong University, Jinan, Shandong Province, China.
authors.forename: Yongmei
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Clinical Laboratory, Qilu Hospital, Shandong University, Jinan, Shandong Province, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Clinical Laboratory, Qilu Hospital, Shandong University, Jinan, Shandong Province, China.
authors.forename: Lutao
authors.initials: L
authors.lastname: Du
authors.affiliation: Department of Clinical Laboratory, Qilu Hospital, Shandong University, Jinan, Shandong Province, China. cxwang@sdu.edu.cn.
authors.forename: Chuanxin
authors.initials: C
authors.lastname: Wang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen / Q000097:blood; D015179:Colorectal Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000235:genetics* / Q000401:mortality; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D010865:Pilot Projects; D063150:Polycomb Repressive Complex 1 / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods; D011379:Prognosis; D012333:RNA, Messenger / Q000097:blood / Q000235:genetics*; D012372:ROC Curve; D015203:Reproducibility of Results; D047368:Tumor Burden
chemical_list: C069077:BMI1 protein, human; D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D012333:RNA, Messenger; D063150:Polycomb Repressive Complex 1