Determination of ErbB2 protein in breast cancer tissues by different methods. Relationships with other biological parameters

Abstract

Four different methods to measure in parallel the erbB2 protein expression (p185neu) were evaluated in order to: a) compare two enzyme immunoassays with the immunohistochemical assays (IHC) and western blotting (WB) and b) extrapolate eventual relationships between erbB2 and biological parameters. Tissue samples from 248 patients with primary breast cancer were consecutively assayed. We used two different cut-off levels for WB, ELISA, and EIA, defined as follows: 1) the highest level of expression of non malignant tissue was chosen as the discriminant threshold between 'low' and 'elevated' samples: 2) the elevated group was further subdivided into two subgroups: 'intermediate' and 'high', according to their median value. According to the first cut-off, the results were considered 'elevated' in about 52% of cases with the three biochemical methods, while using the second cut-off the percentage lowered to about 26%. Considering this cut-off, the concordance rates between the paired biochemical methods ranged between: 78.4% (WB vs EIA), 93% (ELISA vs EIA), and 82.6% (ELISA vs WB). The comparison between biochemical and immunohistochemical methods gave these concordance rates: 82% (WB vs IHC), 90.5% (ELISA vs IHC), and 85.5% (EIA vs. IHC). According to the first cut off level, 27.5% of tumor samples showed IHC detectable p185 levels, in agreement with other immunohistochemical studies. The relationship between high erbB2 and estrogen and progesterone receptors showed an inverse association. No relationship was found between erbB2 and axillary lymph node positivity or tumor size. In short, the results of the four methods seem generally well correlated; nevertheless, it appears that different methodological approaches of measuring p185neu are not completely equivalent, and there is a need for an authoritative standardization and quality control for clinical applications.

Enzyme-linked immunosorbent assay of epidermal growth factor receptor in lung cancer: comparisons with immunohistochemistry, clinicopathological features and prognosis

“…At least some of the remaining discrepancy may be due to intrumoral heterogeneity. To our knowledge, a detailed comparison of EGFR expression using ELISA and IHC has not been published previously, but some studies have determined the related growth factor receptor pl851ER-2 using NHC and ELISA (Dawkins et al, 1993;Dittadi et al, 1993;Nugent et al, 1994;Piffanelli et al, 1996). In brief, the overall agreement was comparable with that of the present study.…”

Quantitative PCR analysis of c-erb B-2 (HER2/neu) gene amplification and comparison with p185HER2/neu protein expression in breast cancer drill biopsies

“…Studies of p185 HER2/neu expression have been carried out mainly by immuno-histochemistry (reviewed by Revillon et al, 1998;Rozan et al, 1998) and less frequently by Western blotting (Slamon et al, 1987;Tandon et al, 1989) or ELISA (Piffanelli et al, 1996). These approaches provide semi-quantitative estimation of the oncoprotein expression.…”

Serum c-erbB-2 Levels in Monitoring of Operable Breast Cancer Patients

“…Currently the prognosticvalue of overexpressionor amplification of c-erbB-2 in breast cancer is controversial (3)(4)(5)(6). Various methods and criteria m-e used to determine gene amplification and protein overexpression of c-erbB-2 and the clinical utility of c-erbB-2 is under investigation (7,8). Recent studies indicated that overexpression of c-erbB-2 protein was associated with the responsiveness or resistance to chemotherapy or hormonal therapy for breast cancer patients (9)(10)(11).…”