Progesterone receptor a b

Slide-mounted 5-micron sections of FFPE tissue were deparaffinized in xylene and rehydrated in a graded ethanol series. For histology, sections were stained with Eosin-Y (Richard-Allan Scientific, San Diego, CA, USA) and counterstained with hematoxylin (Richard-Allan Scientific). Viable tumor cells in hematoxylin and eosin (H&E) stained slides were quantified by a pathologist. For IHC, heat-induced antigen retrieval was performed in either Tris-EDTA buffer, pH 9 or citrate buffer, pH 6 (VWR; Radnor, PA, USA). Sections were permeabilized in 0.2% Triton X-100 in PBS, and blocked in 5% goat serum in PBS for 30 min. Sections were incubated overnight at 4°C in primary antibody against ER (Dako; Santa Clara, CA, USA; cat.# IR084), Ki67 (BioCare Medical; Pacheco, CA, USA; cat.# 325), cleaved caspase-3 (Cell Signaling Technology; cat.# 9664), or progesterone receptor A/B (Cell Signaling Technology; cat.# 3153). Sections were treated with in 0.3% hydrogen peroxide, and signal was developed using VectaStain Elite ABC-HRP kit and DAB substrate (Vector Laboratories; Burlingame, CA, USA). Sections were counterstained with hematoxylin. IHC staining in each section was quantified in 3 representative microscopic fields at 200x magnification using HALO software (Indica Labs; Alburquerque, NM, USA).