A thin-layer gel filtration assay of cytoplasmic oestrogen receptors. A possible screening method for hormone dependent tumours.

A thin-layer gel filtration system for the assay of oestrogen receptors in target organ tissue samples as small as 50 mg is presented and compared with the sucrose gradient centrifugation method. Only specific high-affinity binding of [(3)H]17β-oestradiol to endometrial cytosol has been observed with the thin-layer gel filtration assay, despite the presence of relatively high levels of nonspecific binding components. The system could be adapted to the clinical determination of oestrogen receptor content in biopsy material from mammary and endometrial tumours and would be of value in predicting hormone dependency.