QUANTITATIVE IMMUNOHISTOCHEMISTRY OF ANDROGEN RECEPTORS IN A MICROSPHERE MODEL SYSTEM AND IN PROSTATE TISSUE-SECTIONS

OBJECTIVE: To evaluate androgen receptor (AX) levels to predict endocr ine therapy response and prognosis. STUDY DESIGN: A sepharose microsph ere model was employed to establish the relationship between level of immunohistochemical staining density and both antigen and primary anti body (F39.4.1) concentration. Subsequently, the results of the model s ystem were compared with the results in routine prostate sections. RES ULTS: A log-linear relationship was observed between optical density ( OD) and primary antibody dilution measured in immunostained, antigen-c oated microspheres with moderate antigen density. Similar titration cu rves were observed in prostate sections at the same dilution range, in dicating that the microsphere model can be extrapolated to routine tis sue sections. With microspheres with high coating density, the log-lin ear range of dilutions shifted to higher dilutions. CONCLUSION: Differ ences in AR levels in prostate tissue sections might be more accuratel y detected by comparison of titration curves of primary antibody than by comparison of OD values at a fixed primary antibody dilution.