title: Evaluating blood levels of neuron specific enolase, chromogranin A, and circulating tumor cells as Merkel cell carcinoma biomarkers.
abstract: BACKGROUND
  Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine skin cancer. Although used to monitor MCC patients, the clinical utility of neuron-specific enolase (NSE) and chromogranin A (ChrA) blood levels is untested. EpCAM-positive circulating tumor cells (CTC) reflect disease status in several epithelial tumors. Here we investigate the use of NSE and ChrA blood levels and CTC counts as biomarkers for MCC disease behavior.
  
  
  METHODS
  NSE and ChrA blood levels from 60 patients with MCC were retrospectively analyzed; 30 patients were additionally screened for CTC. Biomarker values were correlated to clinical parameters.
  
  
  RESULTS
  Despite routine use by some physicians, NSE and ChrA blood levels did not correlate with progression free survival, disease specific survival, or MCC recurrence. We found CTC in 97% of tested MCC patients. CTC counts were elevated in patients with active disease, suggesting their potential use in monitoring MCC.
  
  
  CONCLUSIONS
  NSE and ChrA levels were not effective in predicting outcomes or detecting recurrences of MCC. In contrast, CTC counts have potential utility as a biomarker for MCC disease behavior.
authors: Department of Dermatology, University of Heidelberg, Heidelberg, Germany.
authors: Maria Rita
authors: MR
authors: Gaiser
authors: Dermatology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
authors: Kenneth
authors: K
authors: Daily
authors: Department of Dermatology, University of Heidelberg, Heidelberg, Germany.
authors: Jochen
authors: J
authors: Hoffmann
authors: Department of Internal Medicine I and Clinical Chemistry, University of Heidelberg, Heidelberg, Germany.
authors: Maik
authors: M
authors: Brune
authors: Department of Dermatology, University of Heidelberg, Heidelberg, Germany.
authors: Alexander
authors: A
authors: Enk
authors: Dermatology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
authors: Isaac
authors: I
authors: Brownell
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood*; D015266:Carcinoma, Merkel Cell / Q000097:blood* / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D002452:Cell Count; D053379:Chromogranin A / Q000097:blood*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D010751:Phosphopyruvate Hydratase / Q000097:blood*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D012878:Skin Neoplasms / Q000097:blood* / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D015854:Up-Regulation
chemical_list: D014408:Biomarkers, Tumor; C506150:CHGA protein, human; D053379:Chromogranin A; D010751:Phosphopyruvate Hydratase
keywords: EpCAM; Merkel cell carcinoma; chromogranin A; circulating tumor cells; neuron specific enolase