title: A new clinical cut-off of cytokeratin 19 mRNA copy number in sentinel lymph node better identifies patients eligible for axillary lymph node dissection in breast cancer.
abstract: OBJECTIVE
  Cytokeratin 19 (CK19) mRNA copy number predicts the probability of tumour load in axillary lymph nodes (ALN) and can help in decision-making regarding the axillary dissection. The purpose of this study was to define a new cut-off of CK19 mRNA copy number using the one-step nucleic acid amplification (OSNA) assay on metastatic sentinel lymph nodes (SLN) in order to identify cases at risk of having one or more positive ALN.
  
  
  METHODS
  1296 SLN from 1080 patients were analysed with the OSNA assay. 194 patients with positive SLN underwent ALN dissection and the mean value of CK19 copy number (320 000) of their SLN was set as initial cut-off. Receiver operative characteristics curve identify a best cut-off of 7700 (sensitivity 78%, specificity 57%). A comparison between our and the traditional cut-off (5000) was performed.
  
  
  RESULTS
  The cut-off of 7700 successfully identifies patients with positive ALN (p=0.001, false- negative cases: 17%). In the range between 5000 and 7700, one patient with positive ALN would not undergo axillary dissection, whereas eight patients with negative ALN would be correctly identified.
  
  
  CONCLUSIONS
  We suggest that the level of CK19 mRNA copy number could be the only parameter to consider in the intraoperative management of the axilla.
authors.affiliation: Department of Health Science, School of Medicine, University of Eastern Piedmont "Amedeo Avogadro", Novara, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Deambrogio
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy.
authors.forename: Isabella
authors.initials: I
authors.lastname: Castellano
authors.affiliation: Unit of Pathology, Maggiore Hospital, Novara, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Paganotti
authors.affiliation: Unit of Pathology, Luigi Sacco Hospital, Milan, Italy.
authors.forename: Elisabetta Omodeo
authors.initials: EO
authors.lastname: Zorini
authors.affiliation: Department of Surgery, Luigi Sacco Hospital, University of Milan, Milan, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Corsi
authors.affiliation: Breast Unit, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Bussone
authors.affiliation: Unit of Surgery, Maggiore Hospital, Novara, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Franchini
authors.affiliation: Department of Health Science, School of Medicine, University of Eastern Piedmont "Amedeo Avogadro", Novara, Italy.
authors.forename: Jlenia
authors.initials: J
authors.lastname: Antona
authors.affiliation: Department of Health Science, School of Medicine, University of Eastern Piedmont "Amedeo Avogadro", Novara, Italy.
authors.forename: Umberto
authors.initials: U
authors.lastname: Miglio
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Sapino
authors.affiliation: Unit of Pathology, Luigi Sacco Hospital, Milan, Italy.
authors.forename: Concetta
authors.initials: C
authors.lastname: Antonacci
authors.affiliation: Department of Health Science, School of Medicine, University of Eastern Piedmont "Amedeo Avogadro", Novara, Italy.
authors.forename: Renzo
authors.initials: R
authors.lastname: Boldorini
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D053539:Keratin-19 / Q000235:genetics*; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology*; D008875:Middle Aged; D012333:RNA, Messenger; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D021701:Sentinel Lymph Node Biopsy
chemical_list: D053539:Keratin-19; D012333:RNA, Messenger
keywords: Breast Cancer; Lymph Nodes; Molecular Pathology; Surgery