Estrogen receptor protein (ERP) in multiple tumor specimens from individual patients with breast cancer

Abstract

Patients (29) from whom 2 or more spatially and temporally separate samples of breast carcinoma were obtained for ERP analysis were studied. Differences in ERP were obtained in 24% of all cases studied. The greatest degree of variation was found when comparing a primary tumor with a subsequent metastasis (38%). Among 8 patients with ERP negative (-) primary tumors, 6 had ERP (-) and 2 ERP positive (+) metastases. Among 11 patients with ERP (+) primaries 8 had ERP (+) and 3 ERP (-) metastases. Variations were found in 20% of multiple nonsimultaneous metastases from individual patients. The difference in average interval between cases that did not show variation (9.6 mo.) and those that varied (19.3 mo.) suggests that variation may be more likely to occur with later metastases. There was considerable overlap in the range of intervals. These findings underscore the need to biopsy readily accessible recurrences rather than to rely on the results of prior specimens. There was no apparent consistent relationship of these variations to age, site of specimen, interval between specimens or histologic features of the tissues submitted for analysis. Two patients with an ERP (+) primary tumor had ERP (-) metastases after interval therapy. Similar variations were observed in patients who did not have interval therapy. The data do not permit any definite conclusions as to the effect of chemotherapy or radiation on the ERP properties of mammary carcinoma.