ESTROGEN-RECEPTOR EXPRESSION IN DUCTAL CARCINOMA INSITU OF THE BREAST- RELATIONSHIP TO FLOW CYTOMETRIC ANALYSIS OF DNA AND EXPRESSION OF THE C-ERBB-2 ONCOPROTEIN

The expression of oestrogen receptor protein (ER) was examined in 151 cases of symptomatic or screening detected pure ductal carcinoma in si tu (DCIS) of the breast by immunocytochemical assay (ERICA), in formal in-fixed paraffin-embedded tissue, with the monoclonal antibody H 222 (Abbott). Forty-eight tumours (31.8%) of cases were ER positive. Twent y-seven (17.9%) of cases showed high level ER expression and 21 (13.9% ) of cases showed low level ER immunoreactivity. Significant associati ons of positive tumour ER immunoreactivity and non-comedo architecture chi2 = 6.76; (d.f. = 1): P < 0.001, small cell size chi2 = 4.49; (d.f . = 1): P = 0.034, higher S-phase fraction chi2 = 4.71; (d.f. = 1): P = 0.03 and lack of c-erbB-2 protein overexpression chi2 = 7.96; (d.f. = 1): P<0.01 were identified. No significant associations of ER expres sion and patient age, histological grade of necrosis in DCIS, or DNA p loidy were found. ER expression is detectable in less than one third o f symptomatic and screening detected cases of DCIS, implying that endo crine therapy of DCIS may be a more appropriate form of management for morphological subtypes of DCIS which show higher rates of oestrogen r eceptor expression, particularly those of non-comedo and small cell ty pe.