title: Cytokeratin 18 in plasma of patients with gastrointestinal adenocarcinoma as a biomarker of tumour response.
abstract: BACKGROUND
  Plasma biomarkers may be particularly useful as a predictor or early marker of clinical response to treatment in addition to radiological imaging. Cytokeratin 18 (CK18) is an epithelial-specific cytokeratin that undergoes cleavage by caspases during apoptosis. Measurement of caspase-cleaved (CK18-Asp396) or total cytokeratin 18 (CK18) from epithelial-derived tumours could be a simple, non-invasive way to monitor or predict responses to treatment.
  
  
  METHODS
  Soluble plasma CK18-Asp396 and CK18 were measured by ELISA from 73 patients with advanced gastrointestinal adenocarcinomas before treatment and during chemotherapy, as well as 100 healthy volunteers.
  
  
  RESULTS
  Both CK18-Asp396 and total CK18 plasma levels were significantly higher in patients compared with the healthy volunteers (P=0.015, P<0.001). The total CK18 baseline plasma levels before treatment were significantly higher (P=0.009) in patients who develop progressive disease than those who achieve partial response or stable disease and this correlation was confirmed in an independent validation set. The peak plasma levels of CK18 occurring in any cycle following treatment were also found to be associated with tumour response, but peak levels of CK18-Asp396 did not reach significance (P=0.01, and P=0.07, respectively).
  
  
  CONCLUSIONS
  Plasma levels CK18 are a potential marker of tumour response in patients with advanced gastrointestinal malignancy.
authors: Centre for Oncology and Applied Pharmacology, University of Glasgow, Cancer Research UK Beatson Laboratories, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK.
authors: L C
authors: LC
authors: Scott
authors: T R J
authors: TR
authors: Evans
authors: J
authors: J
authors: Cassidy
authors: S
authors: S
authors: Harden
authors: J
authors: J
authors: Paul
authors: R
authors: R
authors: Ullah
authors: V
authors: V
authors: O'Brien
authors: R
authors: R
authors: Brown
mesh_terms: D000230:Adenocarcinoma / Q000097:blood / Q000188:drug therapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000097:blood / Q000188:drug therapy*; D006801:Humans; D053538:Keratin-18 / Q000097:blood*; D008297:Male; D008875:Middle Aged
chemical_list: D014408:Biomarkers, Tumor; D053538:Keratin-18