Paraformaldehyde-fixed, paraffin embedded human colon carcinoma tissue; Antigen retrieval by boiling in sodium citrate buffer(pH6) for 15min; Block endogenous peroxidase by 3% hydrogen peroxide for 30 minutes; Blocking buffer (normal goat serum) at 37°C for 20min; Antibody incubation with Rabbit Anti-DR4 Polyclonal Antibody, Unconjugated (bs-0591R) at 1:500 overnight at 4°C, followed by a conjugated secondary and DAB staining