ESTROGEN RECEPTOR DETERMINATION IN FINE NEEDLE ASPIRATES OF BREAST CANCER

Fine needle aspirates (FNA) of 41 primary and 4 recurrent breast cancers were analyzed immunocytochemically for estrogen receptor (ER) using monoclonal antireceptor antibodies. When compared to the conventional dextran-coated charcoal (DCC) method applying to histologic biopsies, ERs found in FNA were concordant with those in DCC in a rate of 80%. There was no false positive ER in FNA compared the DCC method. False negative ER was noted in cases with ER value of below 50 fmole/mg by the DCC method.The factors contributing to false negative ER in FNA were histologic heterogenesity of ER and low ER quantity due to low cellularity. The use of monoclonal antiestrogen receptor antibody is effective for analyzing ER in FNA of small or recurrent breast cancers.