IMMUNOHISTOCHEMICAL ANALYSIS OF ESTROGEN-RECEPTORS IN 938 BREAST CARCINOMAS - CONCORDANCE WITH BIOCHEMICAL ASSAY AND PROGNOSTIC-SIGNIFICANCE

Estrogen receptor (ER) expression was retrospectively studied by an im munohistochemical method (IHC) on Bouin-Holland fixed, paraffin-embedd ed tissue sections from 938 primary operable breast cancers resected b etween 1980 and 1986 (median follow-up, 9 years), in which ER contents were routinely assessed by the dextran-coated charcoal method (DCC). By the IHC assay, ER were present in 699 (75%) tumors versus 688 (73%) by the DCC assay. Both assays were in agreement in 818 cases (87.2%), with a sensitivity and a specificity of 91.4% and 76% respectively, A mong the 120 discordant results, 59 were IHC negative, DCC positive (5 0% were >30 fmol/mg) and 61 were DCC negative, IHC positive (58% with 50-90% of stained tumor cells). Whatever the assay, there was a strong correlation with tumor size, nodal status, Scarff-Bloom and Richardso n grade, and progesterone receptor status. In the two assays, ER posit ivity was correlated with a better outcome for the group as a whole, b ut with multivariate analysis ER expression failed to show statistical significance.