title: Frequency of HER2 expression of circulating tumour cells in patients with metastatic or recurrent gastrointestinal cancer.
abstract: BACKGROUND
  The clinical significance of circulating tumour cell (CTC) detection in gastrointestinal (GI) cancer remains controversial and the molecular biological characteristics of CTCs are poorly understood.
  
  
  METHODS
  A total of 87 patients with metastatic or recurrent GI cancer were prospectively enrolled. Circulating tumour cells and their HER2 status were assessed using the CellSearch System.
  
  
  RESULTS
  Among the 62 CTC-positive cases, we found 22 discordant cases (35.5%). Among the HER2-negative primary tumours, 17 of 54 developed HER2-positive CTCs. Five of eight had HER2-negative CTCs among the HER2-positive primary tumours.
  
  
  CONCLUSIONS
  The findings in the current study suggest that it is critical to evaluate the HER2 status of not only the primary tumour but also the CTCs because the metastasising tumour cells are the primary target of systemic therapy.
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Iwatsuki
authors.forename: K
authors.initials: K
authors.lastname: Toyoshima
authors.forename: M
authors.initials: M
authors.lastname: Watanabe
authors.forename: N
authors.initials: N
authors.lastname: Hayashi
authors.forename: T
authors.initials: T
authors.lastname: Ishimoto
authors.forename: K
authors.initials: K
authors.lastname: Eto
authors.forename: S
authors.initials: S
authors.lastname: Iwagami
authors.forename: Y
authors.initials: Y
authors.lastname: Baba
authors.forename: N
authors.initials: N
authors.lastname: Yoshida
authors.forename: A
authors.initials: A
authors.lastname: Hayashi
authors.forename: Y
authors.initials: Y
authors.lastname: Ohta
authors.forename: H
authors.initials: H
authors.lastname: Baba
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000453:epidemiology / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009360:Neoplastic Cells, Circulating / Q000378:metabolism* / Q000473:pathology; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D012008:Recurrence
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human