A comparative assessment of HER2 status in operable breast cancer by real-time RT-PCR and by immunohistochemistry.
BACKGROUND
The most commonly used methods for detecting HER2 gene amplification in breast cancer are immunohistochemistry and fluorescence in-situ hybridization. The aim of this retrospective study was to assess HER2 expression by real-time RT-PCR.


METHODS
Expression of HER2 was analyzed by real-time RT-PCR and immunohistochemistry in specimens of invasive ductal breast cancer tissue obtained from 131 women during radical mastectomy.


RESULTS
There was a highly significant difference in mean relative gene expression between HER2-positive and HER2-negative patients as assessed by immunostaining (22.10+/-41.89 vs. 3.17+/-8.76; p<0.001). With a median follow-up of 56 months, the cancer-specific survival of HER2-positive patients assessed by RT-PCR was worse in all cases and in the node-positive group. In multivariate analysis, HER2 status was an independent prognostic factor in all patients.


CONCLUSIONS
Real-time RT-PCR is a valuable method for determining HER2 status, but the selection of the cut-off point of the relative gene expression differentiating between HER2-negative and -positive tumors is essential.
Potemski
Piotr
P
Department of Chemotherapy, Medical University of Łódź, Copernicus Memorial Hospital, Łódź, Poland. piotrpo@mp.pl
Płuciennik
Elzbieta
E
Bednarek
Andrzej K
AK
Kusińska
Renata
R
Pasz-Walczak
Grazyna
G
Jesionek-Kupnicka
Dorota
D
Watala
Cezary
C
Kordek
Radzisław
R
D000328:Adult; D000368:Aged; D001483:Base Sequence; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism* / Q000401:mortality; D018270:Carcinoma, Ductal, Breast / Q000235:genetics* / Q000378:metabolism* / Q000401:mortality; D017931:DNA Primers / Q000235:genetics; D005260:Female; D005784:Gene Amplification; D018734:Genes, erbB-2; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D011044:Poland / Q000453:epidemiology; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015996:Survival Rate
D017931:DNA Primers; D018719:Erb-b2 Receptor Tyrosine Kinases