title: Quantification of Her-2/Neu gene in breast cancer patients using real time-polymerase chain reaction (Q-PCR) and correlation with immunohistochemistry findings.
abstract: BACKGROUND
  HER-2/neu is a proto-oncogene that encodes a transmembrane tyrosine kinase growth factor which is crucial for stimulating growth and cellular motility. Overexpression of HER-2/neu is observed in 10-35% of human breast cancers and is associated with pathogenesis, prognosis as well as response to therapy. Given the imperative role of HER-2/neu overexpression in breast cancer, it is important to determine the magnitude of amplification which may facilitate a better prognosis as well as personalized therapy in affected patients. In this study, we determined HER-2/neu protein expression by immunohistochemistry (IHC) concurrently with HER-2/neu DNA amplification by quantitative real time-polymerase chain reaction (Q-PCR).
  
  
  METHODS
  A total of 53 paired tissue samples from breast cancer patients were frozen-sectioned to characterize the tumour and normal tissues. Only tissues with 80% tumour cells were used in this study. For confirmation, Q-PCR was used to determine the HER-2/neu DNA amplification.
  
  
  RESULTS
  We found 20/53 (37.7%) of the tumour tissues to be positive for HER-2/neu protein overexpression using IHC. Out of these twenty, only 9/53 (17%) cases were in agreement with the Q-PCR results. The concordance rate between IHC and Q-PCR was 79.3%. Approximately 20.7% of positive IHC cases showed no HER-2/neu gene amplification using Q-PCR.
  
  
  CONCLUSIONS
  In conclusion, IHC can be used as an initial screening method for detection of the HER-2/neu protein overexpression. Techniques such as Q-PCR should be employed to verify the IHC results for uncertain cases as well as determination of HER-2/neu gene amplification.
authors.affiliation: UKM Medical Molecular Biology Institute, Kuala Lumpur, Malaysia. rahmanj@ppukm.ukm.edu.my
authors.forename: Nor Azian
authors.initials: NA
authors.lastname: Abdul Murad
authors.forename: Zuraini Abdul
authors.initials: ZA
authors.lastname: Razak
authors.forename: Rosniza Muhammmad
authors.initials: RM
authors.lastname: Hussain
authors.forename: Sharifah Noor Akmal
authors.initials: SN
authors.lastname: Syed Hussain
authors.forename: Clarence
authors.initials: C
authors.lastname: Ko Ching Huat
authors.forename: Siti Aishah
authors.initials: SA
authors.lastname: Che Md Ali
authors.forename: Norlia
authors.initials: N
authors.lastname: Abdullah
authors.forename: Rohaizak
authors.initials: R
authors.lastname: Muhammad
authors.forename: Naqiyah
authors.initials: N
authors.lastname: Ibrahim
authors.forename: Rahman
authors.initials: R
authors.lastname: Jamal
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D001940:Breast / Q000378:metabolism*; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D004247:DNA / Q000235:genetics; D005260:Female; D005784:Gene Amplification; D006801:Humans; D007124:Immunoenzyme Techniques; D008875:Middle Aged; D011379:Prognosis; D000090063:Proto-Oncogene Mas; D060888:Real-Time Polymerase Chain Reaction; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D004247:DNA; D000090063:Proto-Oncogene Mas; D018719:Erb-b2 Receptor Tyrosine Kinases; C000715470:MAS1 protein, human