BRCA1 gene expression in breast cancer: A correlative study between real-time RT-PCR and immunohistochemistry

Fahd Al-Mulla, Mahera Abdulrahman, Govindarajulu Varadharaj, Nadeem Akhter, Jehoram T. Anim

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41 Citations (Scopus)


Breast cancer is a major cause of cancer-related mortality in women. There are major discrepancies concerning the usefulness of various antibodies in detecting breast cancer susceptibility gene 1 (BRCA1) protein and its subcellular localization. The aim of the present study was to determine the specificity and sensitivity of immunohistochemistry (IHC) as a screening method for demonstrating BRCA1 expression. BRCA1 gene expression in archival paraffin-embedded breast cancer tissues was studied simultaneously at the protein and mRNA levels, and the two findings were compared. Forty-eight archival paraffin-embedded breast cancer tissues were studied for BRCA1 gene expression at protein level by IHC using four different antibodies against different BRCA1 epitopes and at mRNA level using real-time RT-PCR. BRCA1 mRNA expression was reduced or absent in 79% of the samples, and this finding correlated significantly with loss of BRCA1 protein expression in 83% of breast cancer tissues using one BRCA1 antibody studied (AB-1, against N-terminus epitope). The specificity of this antibody was 91.3%, and its sensitivity was 66.6%. There was no significant correlation between BRCA1 mRNA and protein expression as demonstrated by the remaining three antibodies. Antibody 8F7 had the highest sensitivity of 100%, but its specificity was 30.4% if mRNA levels were considered as the reference standard.

Original languageEnglish
Pages (from-to)621-629
Number of pages9
JournalJournal of Histochemistry and Cytochemistry
Issue number5
Publication statusPublished - 1 May 2005


  • BRCA1
  • Breast cancer
  • Immunohistochemistry
  • MRNA
  • Protein
  • Real-time RT-PCR


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