1. ¹Institute of Pathology, Institute of Pathology, University of Bonn Medical School, Bonn, Germany
2. ²Department of Developmental Pathology, Institute of Pathology, University of Bonn Medical School, Bonn, Germany
3. ³Department of Gynecology and Obstetrics, University Hospital of Heidelberg, Heidelberg, Germany

Correspondence: Dr N Friedrichs, MD, Institute of Pathology, University of Bonn Medical School, Sigmund-Freud-Strasse 25, 53127 Bonn, Germany. E-mail: Nicolaus.Friedrichs@ukb.uni-bonn.de

Received 24 May 2004; Revised 30 June 2004; Accepted 30 June 2004; Published online 1 October 2004.

Abstract

Although transcription factors AP-2alpha and AP-2gamma have been implicated in the control of estrogen receptor (ER) and ErbB-2, their impact for breast cancer is still controversial. To better understand the role of AP-2 proteins in mammary neoplasia, the analysis of their spatial expression pattern in normal breast and breast cancer is required. A total of 51 specimens of female breast cancer patients and a tissue microarray containing 93 additional female breast cancer cases were immunohistochemically stained for AP-2alpha, AP-2gamma, ER and ErbB-2. In 70 cases of the tissue microarray, survival data comprising a period of up to 30 years were present. In non-neoplastic breast tissue, AP-2alpha was expressed in the inner glandular cell layer while AP-2gamma was expressed in the outer myoepithelial cell layer. Ductal carcinoma in situ revealed strongly AP-2alpha-positive tumor cells surrounded by a layer of AP-2gamma-positive myoepithelial cells. In invasive carcinoma, expression of AP-2alpha and AP-2gamma was variable. High expression of ER and AP-2alpha showed better survival rates than low expression of these markers. AP-2gamma expression had no effect on survival. These results for the first time reveal a distinct spatial expression pattern of AP-2alpha and AP-2gamma in normal breast and in ductal carcinoma in situ with specific AP-2gamma expression in myoepithelium. High ER and AP-2alpha expression in invasive breast cancer showed favorable survival rates. Therefore, AP-2alpha expression seems to be associated with better prognosis of breast cancer. AP-2gamma expression has no influence on survival reflecting that myoepithelial cells are not involved in the neoplastic process.