title: Comparative analysis of tumor markers and evaluation of their predictive value in patients with colorectal cancer.
abstract: BACKGROUND
  We evaluated the feasibility of CEA/CK20 mRNA and CEA/CA19-9 proteins as tumor markers for colorectal cancer by detecting tumor-specific mRNAs in circulating tumor cells and secreted tumor-specific proteins in the peripheral blood of colorectal cancer patients.
  
  
  METHODS
  Peripheral blood was obtained from 23 healthy volunteers and 46 colorectal cancer patients on the day of initiation of adjuvant chemotherapy after surgery (stages I-III, n = 27) or on the first day of chemotherapy after diagnosis (stage IV, n = 19). Levels of CEA/CK20 mRNA in peripheral blood mononuclear cells (PBMCs) were determined with quantitative real-time reverse transcription polymerase chain reaction, and serum CEA/CA19-9 protein levels were determined by radioimmunoassay.
  
  
  RESULTS
  The detection sensitivity of CK20 mRNA was approximately 1 tumor cell in 1 × 10(7) PBMCs, and that of CEA mRNA was approximately 1 tumor cell in 1 × 10(6) PBMCs. Patients with stage IV colorectal cancer had higher levels of CEA mRNA, CK20 mRNA, and serum CEA than patients at stages I-III. Peripheral blood CEA mRNA levels were predictive of overall survival, while serum protein levels of CEA and CA19-9 had no predictive value.
  
  
  CONCLUSIONS
  Peripheral blood CEA mRNA is a useful marker of overall survival in colorectal cancer patients, that is sensitive and specific.
authors.affiliation: Department of Oncology, The First Affiliated Hospital of Harbin Medical University, Harbin, PR China.
authors.forename: Zhi-Ping
authors.initials: ZP
authors.lastname: Liu
authors.forename: Li-Min
authors.initials: LM
authors.lastname: Li
authors.forename: Xiu-Li
authors.initials: XL
authors.lastname: Liu
authors.forename: Da-Xin
authors.initials: DX
authors.lastname: Zhang
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood / Q000235:genetics*; D018395:CA-19-9 Antigen / Q000097:blood / Q000235:genetics*; D002272:Carcinoembryonic Antigen / Q000097:blood / Q000235:genetics*; D017024:Chemotherapy, Adjuvant; D015179:Colorectal Neoplasms / Q000097:blood / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D053558:Keratin-3 / Q000097:blood / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D009360:Neoplastic Cells, Circulating; D011237:Predictive Value of Tests; D012333:RNA, Messenger / Q000097:blood / Q000235:genetics*; D012334:RNA, Neoplasm / Q000097:blood / Q000235:genetics*; D012016:Reference Values; D016019:Survival Analysis
chemical_list: D014408:Biomarkers, Tumor; D018395:CA-19-9 Antigen; D002272:Carcinoembryonic Antigen; C479360:KRT3 protein, human; D053558:Keratin-3; D012333:RNA, Messenger; D012334:RNA, Neoplasm