Summary Immunohistochemical antibody techniques for detection of oestrogen receptors (ER) were applied to formalin fixed, paraffin embedded sections from 62 primary breast cancers, the metastases of their original regional lymph nodes (29 cases), bone marrow carcinosis (43 cases) and liver metastases (20 cases). Forty per cent of the primary tumours and 31% of the regional lymph node metastases were ER positive; in contrast, less than 20% of liver and bone marrow metastases were ER positive. The The presence of oestrogen receptors (ERs) is associated with a prolonged survival in patients with both primary and recurrent breast cancer. This probability applies both to an increased effect of endocrine therapy in receptor positive patients (Alanko et al., 1985;Howell et al., 1984;Rose et al., 1985) and to qualitative differences between ER positive and negative tumours (Clark et al., 1987;Parl et al., 1984;Shek et al., 1987).The ER status of a given tumour should be regarded as a reflection of the average receptor content from cell clones with varying receptor contents. It is unknown whether clones with different receptor content metastasise to different organs or whether it is the 'average' ER content per se which reflects specific biological subtypes. The purpose of the present study is to describe and to compare the immunohistochemical ER content in primary breast cancer, involved regional lymph nodes and subsequent distant metastases. Moreover, prognostic importance of site-specific differences has been investigated.
Materials and methodsThe patients all participated in a prospective investigation programme for patients with recurrent breast cancer. The organisation and results of this study have been published previously (Kamby et al., 1987b obtain tissue for histological verification of metastasis (Kamby et al., 1987a).All metastatic sites detected within 1 month after the diagnosis of the first site of metastasis were grouped together and designated as the sites of first recurrence. The sites of metastases were recorded according to anatomical location. When the number of sites was calculated, the presence of recurrence in each anatomical location counted for one, irrespective of the number of tumour deposits within each site.Among the 394 evaluable patients who entered the investigation programme, 111 patients had histologically verified liver metastases and/or bone marrow carcinosis. Of these, paraffin embedded specimens from the primary tumour were available from 76 patients. In 14 cases, either the primary tumour specimen (eight patients) or the metastatic tissue (six patients) was not evaluable by the immunohistochemical method. This leaves 62 patients with immunohistochemical ER determination of both the primary tumour and a metastasis. Twenty-nine of the patients had locoregional metastases at the time of primary diagnosis. The ER status of these metastases was also determined.The ER analyses were made on sections from formalin fixed and paraffin embedded tissue blocks from the primary tumour, the co...