title: Tumor type M2 pyruvate kinase expression in gastric cancer, colorectal cancer and controls.
abstract: OBJECTIVE
  Tumor formation is generally linked to an expansion of glycolytic phosphometabolite pools and aerobic glycolytic flux rates. To achieve this, tumor cells generally overexpress a special glycolytic isoenzyme, termed pyruvate kinase type M(2). The present study was designed to evaluate the use of a new tumor marker, tumor M(2)-PK, in discriminating gastrointestinal cancer patients from healthy controls, and to compare with the reference tumor markers CEA and CA72-4.
  
  
  METHODS
  The concentration of tumor M(2)-PK in body fluids could be quantitatively determined by a commercially available enzyme-linked immunosorbent assay (ELISA)-kit (ScheBo Tech, Giessen, Germany). By using this kit, the tumor M(2)-PK concentration was measured in EDTA-plasma of 108 patients. For the healthy blood donors a cut-off value of 15 U/mL was evaluated, which corresponded to 90% specificity. Overall 108 patients were included in this study, 54 patients had a histological confirmed gastric cancer, 54 patients colorectal cancer, and 20 healthy volunteers served as controls.
  
  
  RESULTS
  The cut-off value to discriminate patients from controls was established at 15 U/mL for tumor M(2)-PK. The mean tumor M(2)-PK concentration of gastric cancer was 26.937 U/mL. According to the TNM stage system, the mean tumor M(2)-PK concentration of stage I was 16.324 U/mL, of stage II 15.290 U/mL, of stage III 30.289 U/mL, of stage IV 127.31 U/mL, of non-metastasis 12.854 U/mL and of metastasis 35.711 U/mL. The mean Tumor M(2)-PK concentration of colorectal cancer was 30.588 U/mL. According to the Dukes stage system, the mean tumor M(2)-PK concentration of Dukes A was 16.638 U/mL, of Dukes B 22.070 U/mL, and of Dukes C 48.024 U/ml, of non-metastasis 19.501 U/mL, of metastasis 49.437 U/mL. The mean tumor M(2)-PK concentration allowed a significant discrimination of colorectal cancers (30.588 U/mL) from controls (10.965 U/mL) (P<0.01), and gastric cancer (26.937 U/mL) from controls (10.965 U/mL) (P<0.05). The overall sensitivity of tumor M(2)-PK for colorectal cancer was 68.52%, while that of CEA was 43.12%. In gastric cancer, tumor M(2)-PK showed a high sensitivity of 50.47%, while CA72-4 showed a sensitivity of 35.37%.
  
  
  CONCLUSIONS
  Tumor M(2)-PK has a higher sensitivity than markers CEA and CA72-4, and is a valuable tumor marker for the detection of gastrointestinal cancer.
authors.affiliation: Department of General Surgery, Affiliated Xiehe Hospital of Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China. wavestor@whu.edu.cn
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.forename: Jian-Ying
authors.initials: JY
authors.lastname: Chen
authors.forename: Dao-Da
authors.initials: DD
authors.lastname: Chen
authors.forename: Guo-Bin
authors.initials: GB
authors.lastname: Wang
authors.forename: Ping
authors.initials: P
authors.lastname: Shen
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000201:enzymology* / Q000473:pathology* / Q000556:secondary; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D009367:Neoplasm Staging; D011770:Pyruvate Kinase / Q000378:metabolism*; D012680:Sensitivity and Specificity; D013274:Stomach Neoplasms / Q000201:enzymology* / Q000473:pathology* / Q000556:secondary
chemical_list: D014408:Biomarkers, Tumor; D011770:Pyruvate Kinase