Western blot analysis was performed on whole cell extracts (30 µg lysate) of MDA-MB-231 (Lane 1), MDA-MB-231 treated with IFN gamma (100 ng/mL for 12 hr) (Lane 2), MCF7 (Lane 3) and MCF7 treated with IFN gamma (100 ng/mL for 12 hr) (Lane 4). The blot was probed with Anti-Phospho-STAT1 (Ser727) Polyclonal Antibody (Product # PA5-17635, 1:1,000 dilution) and detected by chemiluminescence using Goat anti-Rabbit IgG (Heavy Chain) Superclonal™ Secondary Antibody, HRP conjugate (Product # A27036, 0.25 µg/mL, 1:4,000 dilution). A 91 kDa band corresponding to Phospho-STAT1 (Ser727) was observed across the cell lines tested and was enhanced upon treatment.