title: Changes in biologic features between primary and recurrent or relapsed breast cancers.
abstract: OBJECTIVE
  Changes in ER, PR and Her2 receptor status between primary and metastatic cancer tissue have been suggested in breast cancer. The frequencies of these changes are still not fully understood. The purpose of this study was to evaluate these changes in breast cancer population of Kuwait.
  
  
  METHODS
  Changes in the biological features between primary and recurrent disease in 70 patients who presented between 2009 and 2012 was studied. Statistical comparisons between groups was done using chi square test while Kaplan Meier method was used to perform analysis of survival after relapse. All analysis was carried out using the IBM-SPSS statistical software.
  
  
  RESULTS
  There was a decrease in ER and PR positivity from 61.4% to 58.6% and 61.4% to 44.3% respectively. The overall change in ER and PR status was 28.5% and 25.7% respectively. There was an increase in the Her2 positivity as the tumor relapsed and overall changes were seen in 5.7% of cases.
  
  
  CONCLUSIONS
  Patients with breast cancer experience change in biological markers through the course of their disease. The changes are more with hormone receptors compared to Her2. Re-biopsy should be considered at relapse if feasible.
  
  
  BACKGROUND
  breast cancer, hormone receptors, Her2 neu, receptors, biological features, changes.
authors.affiliation: Department of Medical Oncology, Kuwait Cancer Control Centre, Kuwait.
authors.forename: S
authors.initials: S
authors.lastname: Al-Awadi
authors.affiliation: Dr. Sanjay Thuruthel, Department of Medical Oncology, Kuwait Cancer Control Centre, P.O. Box 42262, Shuwaikh 70653, Kuwait. Tel. No. 0965-24836179, Email: sthuruthel@hotmail.com.
authors.forename: S
authors.initials: S
authors.lastname: Thuruthel
authors.affiliation: Department of Medical Oncology, Kuwait Cancer Control Centre, Kuwait.
authors.forename: K
authors.initials: K
authors.lastname: Yamini
authors.affiliation: Department of Medical Oncology, Kuwait Cancer Control Centre, Kuwait.
authors.forename: P
authors.initials: P
authors.lastname: Muraligopal
authors.affiliation: Department of Medical Oncology, Kuwait Cancer Control Centre, Kuwait.
authors.forename: I
authors.initials: I
authors.lastname: Maarouf
authors.affiliation: Department of Medical Oncology, Kuwait Cancer Control Centre, Kuwait.
authors.forename: A
authors.initials: A
authors.lastname: Atta