Demonstration of oestrogen and progesterone receptors in freeze-dried, paraffin-embedded sections of breast cancer.

Immunohistochemical evaluation of oestrogen and progesterone receptors is of importance in evaluating human breast tumours. Staining techniques can be performed on snap-frozen, cryostat-cut tissues or, as recently reported, on formalin-fixed, paraffin-embedded tissues. These methods are, however, limited by several drawbacks, including difficulties in retrospective studies and in storage of the material, and the relatively high frequency of false negative results for chemically fixed specimens.