Western blot was performed using Anti-RUNX1 Polyclonal Antibody, (Product # PA5-19638) and 55 kDa, 20 kDa bands corresponding to RUNX1 isoforms were observed in the cell lines and tissue tested, with higher expression in Jurkat, HEL 92.1.7 compared to T-47D and IMR32. Modified whole cell extracts (1% SDS) (40 µg lysate) of Jurkat (Lane 1), HEL 92.1.7 (Lane 2), T-47D (Lane 3), IMR32 (Lane 4), Mouse thymus (lane 5) and Mouse brain (Lane 6) were electrophoresed using Novex® NuPAGE® 4-12 % Bis-Tris gel (Product # NP0321BOX). Resolved proteins were then transferred onto a nitrocellulose membrane (Product # IB23001) by iBlot® 2 Dry Blotting System (Product # IB21001). The blot was probed with the primary antibody (0.5 µg/mL) and detected by chemiluminescence with Goat anti-Rabbit IgG (Heavy Chain), Superclonal™ Recombinant Secondary Antibody, HRP conjugate (Product # A27036, 1:4000 dilution) using the iBright FL 1000 (Product # A32752). Chemiluminescent detection was performed using Novex® ECL Chemiluminescent Substrate Reagent Kit (Product # WP20005).