Comparison of biochemical and histochemical techniques for estrogen receptor analyses in mammary carcinoma

Three histochemical techniques for estrogen binding localization in tissue sections were compared to sucrose density gradient analyses for estrogen receptor in 186 breast carcinomas. Apparent localization to epithelial elements was noted using 6‐BSA‐Fluor‐CMO‐17β‐estradiol, 17‐BSA‐Fluor‐TSC‐estrogen, and polyestradiol phosphate/anti‐estradiol antibody methods. The correlation between the histochemical methods and standard sucrose density gradient techniques was poor for the polyestradiol antibody method and the 6‐BSA‐Fluor‐CMO‐17/β‐estradiol technique. While an improved correlation was observed with the 17‐BSA‐Fluor‐TSC‐estrogen compound, the compound's binding was not effectively blocked by preincubation with diethylstilbestrol. This failure to show convincing saturability of binding, combined with problems of extraction of soluble receptor proteins in the aqueous incubation media and washes from cells rendered permeable by cryostat sectioning, indicates that several areas will require clarification before histochemical techniques can begin to be considered as a method for estrogen “receptor” analyses in the clinical evaluation of breast neoplasms.