Paraformaldehyde-fixed, paraffin embedded (Rat breast); Antigen retrieval by boiling in sodium citrate buffer (pH6.0) for 15min; Block endogenous peroxidase by 3% hydrogen peroxide for 20 minutes; Blocking buffer (normal goat serum) at 37°C for 30min; Incubation: Anti-VEGFR2 Antibody, conjugated (SL0565R-FITC) at 1:100 overnight at 4°C; DAPI (5ug/ml, blue, SLC0033) was used to stain the cell nuclei.