Western blot was performed using Anti-Rb Polyclonal Antibody (Product # PA5-27215) and a 110 kDa band corresponding to Retinoblastoma-associated protein was observed across the cell lines and tissues tested. Modified whole cell extracts (1% SDS) (30 µg lysate) of MCF7 (Lane 1), LNCaP (Lane 2), HeLa (Lane 3), A-431 (Lane 4), SW480 (Lane 5) and tissue extracts (30 µg lysate) of Mouse Retina (Lane 6) and Rat Retina (Lane 7) were electrophoresed using NuPAGE™ 4-12% Bis-Tris Protein Gel (Product # NP0322BOX). 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 with Goat anti-Rabbit IgG (Heavy Chain) Superclonal™ Recombinant Secondary Antibody, HRP (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). An uncharacterized band of ~70 kDa was also observed in LNCaP, ~50 kDa band in A431 and ~32 kDa bands in LNCaP, A431 and SW480.