Diaminobenzidine chromogen dab

The paraffin-embedded tissue samples were collected from 20 women with primary epithelial ovarian cancer, stagesIIto IV, who had undergone initial surgery at the department of obstetrics and gynecology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University between 2005–2008. The slides were deparaffinized, rehydrated and placed into citric acid buffer (pH 6.0, 0.1 M) for heating for 10 min. The endogenous peroxidase activity was then blocked by incubation with 3% H₂O₂ for 10 min. Afterwards, sections were incubated with blocking buffer (Beyotime, China) for 1 h and then incubated overnight at 4°C with FOXM1 antibody (1∶50, Santa Cruz). Following a 10-min incubation of biotinylated second antibody, the slides were again incubated with streptavidin-peroxidase under the same condition. The immunoreaction was then visualized by incubation with diaminobenzidine chromogen (DAB, Maixin-Bio, China) for 5 min. Finally, the slides were counterstained with hematoxylin, dehydrated, cleared and mounted. Negative controls were incubated in blocking buffer alone. These results were only considered if these control samples demonstrated a negative staining.