COMPARISON OF STANDARDIZED IMMUNOHISTOCHEMICAL AND BIOCHEMICAL ASSAYSFOR ESTROGEN AND PROGESTERONE RECEPTORS IN BREAST-CARCINOMA

The purpose of this study was to determine estrogen receptor (ER) and progesterone receptor (PR) expression assessed by dextran-coated charc oal method (DCC) and standardized immunohistochemical method (IHC) in a prospective series of 557 primary breast carcinomas, to assess the c oncordance between the two assays, and to evaluate the association bet ween hormone receptor expression and various clinicopathological param eters. For ER, results of both methods were in agreement in 73.6% of t he cases (277 positive, 133 negative), 74 tumors (13.3%) where IHC+/DC C- and 73 (13.1%) were IHC-/DCC+. For PR, concordant results were obse rved in 72.7% of the cases (201 positive and 204 negative), 127 tumors (22.8%) were IHC+/DCC- and 25 (4.5%) were IHC-/DCC+. Irrespective of the method used, ER and PR positivity showed a strong negative associa tion with tumor grade. ER+ tumors were significantly more common among older patients. With IHC, PR(+)cases were more common among tumors of lobular and mucinous type and among node positive tumors. The only pa rameter that was related to the concordance rate of ER determination b y the DCC and IHC method was the age of the patients, with agreement b eing significantly lower in the group of patients younger than 50 year s. On the other hand, discordant PR determination was more often obser ved in tumors of lower grade, node positive tumors and in tumors of lo bular and mucinous type.