Western blot was performed using Anti-DLL3 Recombinant Rabbit Monoclonal Antibody (Product # 703075) and a 63 kDa band corresponding to DLL3 was observed across the cell lines tested. Membrane enriched extracts (30 µg lysate) of A-375 (Lane 1), A549 (Lane 2) and U-87 MG (Lane 3) 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 (1:1000 dilution) and detected by chemiluminescence Goat Anti-Rabbit IgG Secondary Antibody, HRP conjugate (Product # A27036, 1:4000 dilution). Chemiluminescent detection was performed using Novex® ECL Chemiluminescent Substrate Reagent Kit (Product # WP20005).