IMMUNOHISTOCHEMICAL DEMONSTRATION OF ANDROGEN RECEPTOR IN BREAST-CANCER AND ITS RELATIONSHIP TO OTHER PROGNOSTIC FACTORS

Androgen actions and androgen receptors (ARs) have been described in h uman breast cancer cells both in vivo and in vitro. With the use of a new monoclonal anti-AR antibody, AR was immunohistochemically demonstr ated in 76 primary breast cancers. Positive immunostaining was found i n 79 per cent of tumours. Benign ductal epithelium was often AR-positi ve whereas the tumour stroma lacked AR immunoreactivity. At the subcel lular level, nuclear localization was evident using either cross-linki ng (Zamboni's fluid) or precipitating (acetone) fixatives on frozen se ctions. The use of archival paraffin-embedded tissue yielded negative results. A significant association was found between expression of AR and oestrogen receptor (ER) (P=0.0006) determined immunohistochemicall y on adjacent sections. Most progesterone receptor (PR)-negative cases were also AR-negative (P=0.02), but significant proportion (38 per ce nt) of AR-positive tumours did not contain PR. Unlike ER, AR was not a ssociated with aneuploidy or erb-B2 oncogene overexpression, and was o nly marginally associated with tumour proliferation rate (S-phase frac tion by DNA flow cytometry). In conclusion, the close association of A R with ER and PR suggests that immunohistochemical determination of an drogen receptors may have value as a prognostic factor and/or predicto r of response to endocrine therapy.