Cellularity and the quantitation of estrogen receptors.

Fifty estrogen receptor (ER)-positive breast cancers have been studied to determine the best way of correcting for differences in cellularity when expressing ER concentration. ER concentration expressed on wet weight and tumour cytosol protein bases showed a positive correlation with tumour cellularity. In contrast, ER concentrations expressed on a DNA basis were not significantly related to cellularity. Although such a mode of correcting for differences in cellularity was imperfect, it did yield a receptor concentration which was less dependent upon tissue cellularity and which may reflect more accurately the inherent receptor status of the tumour cells.