Published in Cancer Detection and Prevention 1997; 21(1):29-35.

Simultaneous Quantitative Analyses of c-erbB-2 Protein, Epidermal Growth Factor Receptor, Cathepsin D, and Hormone Receptors in Breast Cancer

Hirotaka Iwase, MD, Yukashi Itoh, MD, Tatsuya Kuzushima, MD, Hiroko Yamashita, MD, Hiroji Iwata, MD, Tatsuya Toyama, MD, Yasuo Hara, MD, Shunzo Kobayashi, MD

Second Department of Surgery, Nagoya City University Medical School, Nagoya, Japan

Address all correspondence and reprint requests to: Hirotaka Iwase, MD, The Second Department of Surgery, Nagoya City University Medical School, Kawasumi 1, Mizuho-ku, Nagoya 467, Japan

ABSTRACT: The overexpression of c-erbB-2 protein (ErbB2), epidermal growth factor receptor (EGFR), and/or cathepsin D (CD) in breast cancer is known to be a poor prognostic factor. Eighty frozen breast cancer specimens obtained at the initial operation were examined for ErbB2, EGFR, and CD by immunohistochemical assay (ICA) and enzyme immunoassay (EIA). Estrogen and progesterone receptors (ER and PgR) were measured simultaneously by EIA. The mean values +/- 1SD for ErbB2, EGFR, and CD were 141 +/- 400 U/mg membrane protein (range: 0- 3385), 4.88 +/- 4.33 fmol/mg membrane protein (range: 0-21.1), and 47.1 +/- 32.8 pmol/mg cytosol protein (range: 4.7-182), respectively. The percentage of specimens positive for ErbB2, EGFR, and CD was 12.5, 38.8, and 35%, when the tentative cutoff value were used as 200 U/mg protein, 5 fmol/mg protein, and 50 pmol/mg protein, respectively. These EIA results were correlated with ICA. EGFR and ER were negatively correlated. Although the prognostic value of ErbB2 and EGFR was superior to hormone receptors, ErbB2 and EGFR were inferior as predictors compared with lymph node involvement and tumor size. Quantitation of ErbB2, EGFR, and CD can be performed readily using the same specimen in which hormone receptors are measured.

KEY WORDS: prognostic factor, c-erbB-2, epidermal growth factor receptor, cathepsin D, enzyme immunoassay.