Steroid receptor levels in breast cancer. Relationships with age and menopausal status

The paper presents descriptive data concerning relationships between age, menopausal status and steroid receptor content in primary breast carcinoma. The study was based on 2,329 women with primary breast carcinoma diagnosed in Stockholm county during 1980-1983. Oestrogen (ER) and progesterone receptor (PgR) content was determined using the isoelectric focusing technique. All analyses were done in one laboratory. There was a gradual increase in mean ER values with age. Premenopausal patients had lower mean ER values than peri- and postmenopausal patients of the same age. In contrast, PgR levels were similar in different age-groups. This could be a result of an insufficient stimulation of the tumour cells via the ER pathway. It is also possible that the PgR stimulation is maximal already at ER values below those found in old patients. It is concluded that steroid receptor content measured with commonly used ligand assays may reflect both biological properties of the tumour cells as well as influences by nontumoural factors, e.g. the endogenous levels of sex hormones.