Preoperative assessment of HER-2/neu status in breast carcinoma: The role of quantitative real-time PCR on core-biopsy specimens

Abstract

Objectives Knowledge of HER-2/neu status is mandatory to identify breast cancer patients amenable to trastuzumab treatment. We evaluated the diagnostic performance of quantitative real-time polymerase chain reaction (qRT-PCR) in the preoperative determination of HER-2/neu status in breast cancer, using core biopsy material. Methods In a prospective series, qRT-PCR was performed on fresh core biopsy specimens taken preoperatively in 87 patients with breast carcinoma. Cases with qRT-PCR ratio ≥ 2.0 were considered to have HER-2/neu amplification. The results of RT-PCR analysis were compared with those of the standard immunohistochemistry (IHC) and Fluorescence in situ hybridization (FISH) methods. Cases with IHC 3+ or with IHC 2+ and FISH showing amplification were considered HER-2/neu positive. All other cases were considered HER-2/neu negative. Results qRT-PCR showed HER-2/neu amplification in 13 cases (14.9%), while the standard IHC-FISH combined approach identified 17 HER-2/neu-positive cases (19.5%). Overall, there was concordance between methods in 83 of 87 patients (95.4%). The Spearman's rho correlation coefficient was 0.851; p < 0.001. The diagnostic performance for preoperative diagnosis of HER-2/neu status using RT-PCR on core biopsy specimens as compared to standard approach was as follows: sensitivity 76.5%; specificity 100%; positive predictive value 100%; negative predictive value 94.6%. Conclusions Quantitative RT-PCR determination of HER-2/neu status from core biopsy specimens provided results comparable to those given by the standard IHC and FISH methods. The use of qRT-PCR on core biopsy material may represent a very useful and easy tool to enhance early identification of HER-2/neu-positive breast cancer patients who, possibly can benefit from trastuzumab treatment.