title: Discordance between core needle biopsy (CNB) and excisional biopsy (EB) for estrogen receptor (ER), progesterone receptor (PgR) and HER2 status in early breast cancer (EBC).
abstract: BACKGROUND
  Analysis of estrogen receptor (ER), progesterone receptor (PgR) and HER2 status in early breast cancer (EBC) is increasingly being conducted in core needle biopsies (CNBs) taken at diagnosis but the concordance with the excisional biopsy (EB) is poorly documented.
  
  
  METHODS
  Patients with EBC presenting to The Royal Marsden Hospital from June 2005 to September 2007 who had CNB and subsequent EB were included. ER and PgR were determined by immunohistochemistry (IHC) and graded from 0 to 8 (Allred score). HER2 was determined by IHC and scored from 0 to 3+. FISH analysis was carried out in HER2 2+ cases and in discordant cases.
  
  
  RESULTS
  In all, 336 pairs of samples were compared. ER was positive in 253 CNBs (75%) for 255 EBs (76%) and was discordant in six patients (1.8%). PgR was positive in 221 CNBs (66%) and 227 (67.6%) EBs being discordant in 52 cases (15%). HER2 was positive in 41 (12.4%) of the 331 CNBs in which it was determined compared with 44 (13.3%) EBs and discordant in four cases (1.2%).
  
  
  CONCLUSIONS
  CNB can be used with confidence for ER and HER2 determination. For PgR, due to a substantial discordance between CNB and EB, results from CNB should be used with caution.
authors: Department of Medicine, Breast Unit, The Royal Marsden Hospital and Institute of Cancer Research, London, UK. monica.arnedos@rmh.nhs.uk
authors: M
authors: M
authors: Arnedos
authors: A
authors: A
authors: Nerurkar
authors: P
authors: P
authors: Osin
authors: R
authors: R
authors: A'Hern
authors: I E
authors: IE
authors: Smith
authors: M
authors: M
authors: Dowsett
mesh_terms: D001706:Biopsy / Q000379:methods*; D001707:Biopsy, Needle / Q000379:methods*; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*; D015203:Reproducibility of Results
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human