title: Determination of the HER2 amplification status by in situ fluorescent hybridization and concordance with immunohistochemistry for breast cancer samples in Colombia.
abstract: OBJECTIVE
  To determine the status of the HER2 amplification in Breast cancer performed in peripheral laboratories in Colombia by immunohistochemistry and its comparison with central laboratories and the FISH status.
  
  
  METHODS
  Four thousand one hundred and five cases referred for the determination of the HER2 status by FISH and/or IHQ to the Department of Pathology of the Fundacion Santa Fe were studied. The analysis included correlation between the IHQ HER2 score submitted by the peripheral laboratory (PL), the HER2 score emitted in the CL and the FISH studies performed in the central laboratory (CL).
  
  
  RESULTS
  Two thousand five hundred and eight HER2 IHQ studies were performed in the (CL), using the Dako Herceptest. With the following results: 68.2 % negative (0-1+); 16,4% indeterminate (2+); 15.3% 3+ and 2.3 % not adequate. 1360/ 1719 cases studied by FISH came from the (PL), and 329 (19.1%) from the (CL). Comparing the IHQ score emitted by the PL and the positive FISH status showed: 6/28 0+ were positive (21. 4%); 7/31 1+ (22. 5%); 397/1240 2+ (32.8%) and 74/91 3+ (81. 3%). In the CL the results were 1/9 0+ (11.1%); 3/18 1+ (16.7%); 154/292 2+ (53%); and 9/9 3+ (100%). Only 1/4 negative cases (0/1+) was in house.
  
  
  CONCLUSIONS
  The false negative rate (22%), and false positive results (18.7%), of the HER2 status performed by IHQ in peripheral laboratories in Colombia is unacceptable high as well as the inadequacy of tissue indicating that pre-analytical factors have to be improved in Colombia in order to get optimal results.
authors.affiliation: Departament of Pathology & Laboratories. University Hospital Fundación Santa Fe de Bogotá. Bogotá. Colombia. E-mail: rafael.andrade@fsfb.org.co.
authors.forename: Adriana
authors.initials: A
authors.lastname: Plata
authors.affiliation: Laboratory of Human Genetics. School of Sciences. Universidad de los Andes. Bogotá, Colombia. E-mail: maritorr@uniandes.edu.co.
authors.forename: Maria Mercedes
authors.initials: MM
authors.lastname: Torres
authors.affiliation: Departament of Pathology & Laboratories. University Hospital Fundación Santa Fe de Bogotá. Bogotá. Colombia. E-mail: rafael.andrade@fsfb.org.co.
authors.forename: Rocío
authors.initials: R
authors.lastname: López
authors.affiliation: Departament of Pathology & Laboratories. University Hospital Fundación Santa Fe de Bogotá. Bogotá. Colombia. E-mail: rafael.andrade@fsfb.org.co.
authors.forename: Rafael E
authors.initials: RE
authors.lastname: Andrade
keywords: FISH; HER2; Immunohistochemistry; breast cancer