BACKGROUND: Long-term antiestrogen therapy has been suggested as a possible treatment alternative for ductal carcinoma in situ (DCIS) of the breast. However, very little information is available on the distribution of estrogen receptor (ER) and treatment success with antiestrogen for such lesions. METHODS: Thirty-two formalin-fixed tissue specimens of DCIS from 32 female patients aged 38 to 71 years were evaluated for the presence of ER by an immunoperoxidase technique. Antigenic sites for ER were exposed by treating the tissue sections with deoxyribonuclease followed by peroxidase-antiperoxidase staining with monoclonal antibody against ER. Parallel negative controls were run with negative control monoclonal antibody and normal rat serum. The quality control for positive staining was performed with tissue sections from specimens with known ER detected by the radioreceptor method. RESULTS: Eighteen (60%) of the 32 lesions were positive for ER. In 7 of the 18 lesions less than 25% of cells stained positive for ER and in 4 of the 18 more than 50% of cells stained positive for ER. CONCLUSIONS: The incidence of ER in DCIS is similar to the incidence of ER in invasive carcinoma, leading to the speculation that ER-positive invasive carcinoma originates from an ER-positive precursor lesion. Because only 60% of the cases have detectable ER and approximately 70% of positively stained ERs are expected to be functional (as in invasive carcinoma), it appears that approximately 42% of the patient population with DCIS will benefit from antiestrogen therapy.
BACKGROUND: Long-term antiestrogen therapy has been suggested as a possible treatment alternative for ductal carcinoma in situ (DCIS) of the breast. However, very little information is available on the distribution of estrogen receptor (ER) and treatment success with antiestrogen for such lesions. METHODS: Thirty-two formalin-fixed tissue specimens of DCIS from 32 female patients aged 38 to 71 years were evaluated for the presence of ER by an immunoperoxidase technique. Antigenic sites for ER were exposed by treating the tissue sections with deoxyribonuclease followed by peroxidase-antiperoxidase staining with monoclonal antibody against ER. Parallel negative controls were run with negative control monoclonal antibody and normal rat serum. The quality control for positive staining was performed with tissue sections from specimens with known ER detected by the radioreceptor method. RESULTS: Eighteen (60%) of the 32 lesions were positive for ER. In 7 of the 18 lesions less than 25% of cells stained positive for ER and in 4 of the 18 more than 50% of cells stained positive for ER. CONCLUSIONS: The incidence of ER in DCIS is similar to the incidence of ER in invasive carcinoma, leading to the speculation that ER-positive invasive carcinoma originates from an ER-positive precursor lesion. Because only 60% of the cases have detectable ER and approximately 70% of positively stained ERs are expected to be functional (as in invasive carcinoma), it appears that approximately 42% of the patient population with DCIS will benefit from antiestrogen therapy.