G. Szekeres et al., STEROID-HORMONE RECEPTOR IMMUNOSTAINING ON PARAFFIN SECTIONS WITH MICROWAVE-HEATING AND TRYPSIN DIGESTION, Journal of histotechnology, 17(4), 1994, pp. 321-324
A recently described antigen retrieval method with microwave heating o
f tissue sections was combined with trypsin digestion to increase the
immunostaining intensity of estrogen and progesterone receptors. We us
ed 2 new monoclonal antibodies, the estrogen receptor (ER)-specific ER
/D5 and the progesterone receptor (PR)-specific PR10A9 to detect hormo
ne receptors in tissue sections of routinely fixed and embedded breast
cancer specimens. These 2 antibodies react with their antigens only f
ollowing microwave pretreatment of the fixed-embedded sections. When w
e used trypsin digestion before the microwave heating, the intensity o
f nuclear hormone receptor immunostaining increased. In some cases, we
also found cytoplasmic and/or membrane-associated staining when using
the PR-specific PR10A9 antibody. However, when we used trypsin digest
ion following the microwave heating, the nuclear staining intensity of
ER decreased and that of PR increased. We also observed a loss or sig
nificant decrease of the cytoplasmic and membrane-associated component
s of PR immunostaining. We suggest that by using 2 different tissue pr
etreatment protocols, we can distinguish between the 2 different forms
of the 2 steroid hormone receptors.