Western Blot was performed using Anti-M-CSF Monoclonal Antibody (21113) (Product # MA5-23708), and a 44 kDa band corresponding to Macrophage colony-stimulating factor 1 was observed in SK-BR-3 but not in Raji which is reported to be low or negative for M-CSF expression. Whole cell extracts (60 µg lysate) of SK-BR-3 (Lane 1) and Raji (Lane 2) were electrophoresed using NuPAGE™ 4-12% Bis-Tris Protein Gel (Product # NP0322BOX). Resolved proteins were then transferred onto a Nitrocellulose membrane (Product # IB23002) by iBlot® 2 Dry Blotting System (Product # IB21001). The Blot was probed with the primary antibody (1 µg/mL) and detected by chemiluminescence with Goat anti-Mouse IgG (H+L) Superclonal™ Recombinant Secondary Antibody, HRP (Product # A28177, 1:4000 dilution) using the iBright FL 1000 (Product # A32752). Chemiluminescent detection was performed using Novex® ECL Chemiluminescent Substrate Reagent Kit (Product # WP20005).