ABSTRACT
There is controversy as to the validity of histochemical techniques to localize estrogen receptors (ER) in human breast cancer. Using an estrogen bovine serum albumin fluorescein iso-thiocyanate (BSA FITC) complex, several groups have attempted to evaluate the presence of steroid receptors at the cellular level in frozen sections or in cell suspensions of human breast cancer. The results of comparing histochemical and biochemical assays in group 1 and 2 indicate that a tumor which will be labeled as positive or negative for estrogen binding by the histochemical technique will be similarly called by the biochemical assay. Problems in evaluating the results of the histochemical technique come from the fact that there is no established cutoff point to distinguish between negative and positive tumors using the percentage of positive cells and the intensity of fluorescence. This also hampers the correlation between the histochemical and biochemical techniques.
