Sex-steroid receptors in human breast cancer. Incidence and interrelationships.
Over-expression of oestrogen and progesterone receptor (ER and PR respectively) has been reported in malignant breast disease but the techniques employed have been relatively insensitive and prone to underestimations. Using a highly sensitive microassay method, we have estimated ER (n = 39), PR (n = 32) and androgen receptor (AR) (n = 37) in cytosolic and nucleosolic fractions obtained from the same tissue samples. Induction of PR by oestrogen is a widely recognized phenomenon, and a relationship between PR and ER is to be expected. There is evidence that sex-steroids and their receptors act in concert and it is therefore surprising that AR has been poorly studied in malignant breast disease, despite indications that its presence increases hormone responsiveness. Our hypothesis is that, unlike the normal breast, in malignancy a possible deregulation of transcriptional control may lead to an over expression of all three classes of sex-steroid receptor. Using the microassay, we have tested this hypothesis and found not only a greater incidence of ER, AR and PR than previously reported in malignant breast disease, but considerably higher levels of these receptors. In addition, our findings demonstrate that these receptors tend to be expressed simultaneously rather than discretely, supporting the view that a deregulation of transcriptional control may account for the clinical and biological heterogeneity of the disease.
Valyani
S H
SH
Department of Surgery, Rayne Institute, Kings College Hospital of Medicine and Dentistry, London, U.K.
Roberts
J V
JV
Colletta
A A
AA
Iqbal
M J
MJ
D001943:Breast Neoplasms / Q000032:analysis*; D002466:Cell Nucleolus / Q000032:analysis; D003600:Cytosol / Q000032:analysis; D005260:Female; D006801:Humans; D008832:Microchemistry / Q000379:methods; D011944:Receptors, Androgen / Q000032:analysis*; D011960:Receptors, Estrogen / Q000032:analysis*; D011980:Receptors, Progesterone / Q000032:analysis*
D011944:Receptors, Androgen; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone