title: Creatine Kinase (CK)-MB-to-Total-CK Ratio: a Laboratory Indicator for Primary Cancer Screening.
abstract: BACKGROUND
  For the determination of creatine kinase (CK)-MB, the immunoinhibition method is utilized most commonly. However, the estimated CK-MB activity may be influenced by the presence of CK isoenzymes in some conditions like cancer. Thus, a CK-MB-to-total-CK ratio more than 1.0 could be found in such a situation. The study aimed to explore the relationship of cancer to high CK-MB-to-total-CK ratio.
  
  
  METHODS
  From January 2011 to December 2014, laboratory data on all CK-MB and total CK test requests were extracted at Far Eastern Memorial Hospital (88,415 requests). Patients with a CK-MB-to-total-CK ratio more than 1.0 were registered in this study. Clinical data including tumor location, tumor TNM stage and metastatic status were also collected.
  
  
  RESULTS
  A total of 846 patients were identified with a CK-MB-to-total-CK ratio more than 1.0. Of these, 339 (40.1%) were diagnosed with malignancies. The mean CK-MB-to-total-CK ratio was significantly higher in malignancy than in non-malignancy (1.35±0.28 vs 1.25±0.23, p<0.001) groups. The most frequent malignancy with a CK-MB-to-total-CK ratio more than 1.0 was colorectal cancer (1.42±0.28, 16.5%, n=56), followed by lung cancer (1.38±0.24, 15.9%, n=54) and hepatocellular carcinoma (14.5%, n=49). Higher CK-MB-to-total-CK ratios in hematological malignancies (1.44±0.41)were also noted. Additionally, the CK-MB-to-total-CK ratio was markedly higher in advanced stage malignancy than in early stage (1.37±0.26 vs. 1.29±0.31, p=0.014) and significantly higher in liver metastasis than in non-liver metastasis (1.48±0.30 vs. 1.30±0.21, p<0.001).
  
  
  CONCLUSIONS
  The CK-MB-to-total-CK ratio is an easily available indicator and could be clinically utilized as a primary screening tool for cancer. Higher ratio of CK-MB-to-total-CK was specifically associated with certain malignancies, like colorectal cancer, lung cancer and hepatocellular carcinoma, as well as some cancer-associated status factors such as advanced stage and liver metastasis.
authors.affiliation: Department of Clinical Pathology, Far Eastern Memorial Hospital, New Taipei City, Taiwan E-mail : jacpha@mail.femh.org.tw.
authors.forename: Chih-Chun
authors.initials: CC
authors.lastname: Chang
authors.forename: Ching-Biau
authors.initials: CB
authors.lastname: Liou
authors.forename: Ming-Jang
authors.initials: MJ
authors.lastname: Su
authors.forename: Yi-Chen
authors.initials: YC
authors.lastname: Lee
authors.forename: Chai-Ting
authors.initials: CT
authors.lastname: Liang
authors.forename: Jung-Li
authors.initials: JL
authors.lastname: Ho
authors.forename: Huang-Wen
authors.initials: HW
authors.lastname: Tsai
authors.forename: Tzung-Hai
authors.initials: TH
authors.lastname: Yen
authors.forename: Fang-Yeh
authors.initials: FY
authors.lastname: Chu
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood*; D016022:Case-Control Studies; D004796:Clinical Enzyme Tests; D003402:Creatine Kinase / Q000097:blood; D052279:Creatine Kinase, MB Form / Q000097:blood*; D055088:Early Detection of Cancer / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D009369:Neoplasms / Q000097:blood* / Q000473:pathology*; D012189:Retrospective Studies
chemical_list: D014408:Biomarkers, Tumor; D003402:Creatine Kinase; D052279:Creatine Kinase, MB Form