Mouse on mouse m o m blocking reagent mkb 2213

All antibodies are described in the Supplementary Information. Patient samples were collected under IRB exemption approval for protocol #EX21205258-1. Paraffin embedded sections were rehydrated through a xylene and alcohol series, rinsed in H₂O and washed in PBS. Antigen retrieval was performed using target retrieval buffer (Vector Labs, Burlingame, CA) and steamed for 20 min. Samples were then blocked in a peroxidase blocking buffer (Thermo Scientific) for 15 min, followed by Protein block (Thermo Scientific) for 5 min, and incubated in appropriate primary antibody diluted in antibody diluent (S0809, Dako) at 4°C overnight in a humidified chamber. For mouse samples to be incubated with anti-mouse antibody, samples were blocked for 1 hour in Mouse on Mouse (M.O.M.™) Blocking Reagent (MKB-2213, Vector Labs). Following washing in PBS, samples were incubated in biotinylated anti-rabbit or polyvalent secondary antibody (Thermo Scientific) followed by streptavidin-HRP solution at room temperature for 20 min. Samples were then washed in PBS and incubated in 3-Amino-9-Ethyl-l-Carboazole (AEC) chromogen and counter stained with Mayers hematoxylin for 1 min, rinsed in cold H₂O, and mounted in Aquamount.