Immunofluorescent analysis of Estrogen Receptor alpha (ER alpha, green) in T47D and Hs 578T breast cancer cells. The cells were fixed and permeabilized with ice-cold methanol for 10 minutes at room temperature, and blocked with 0.3% BSA in PBS for at least 30 minutes at room temperature. Cells were stained with an ER alpha monoclonal antibody (Product # MA5-14104) at a dilution of 1:100 in blocking buffer overnight at 4C, and then incubated with a DyLight 488-conjugated goat anti-mouse IgG secondary antibody (Product # 35502) at a dilution of 1:500 for at least 1 hour at room temperature. Nuclei (blue) were stained with DAPI (Product # 62247). Images were taken on a Thermo Scientific ToxInsight Instrument at 20X magnification.