2.7. Immunohistochemistry (IHC)
After deparaffinization in prostate tissues, immune histochem- istry (IHC) was performed on 10-lm-thick sections. Antigen retrieval was performed using citrate buffer, pH 6.0, for 10 min prior to peroxide quenching with 3% H2O2 in phos- phate buffered saline (PBS) for 15 min. The prostate tissues were then washed in PBS and preblocked with normal goat or rabbit serum for 10 min. For reaction with primary anti- body, slides were incubated with anti-transforming growth fac- tor – b1 (TGF-B1) (Santa Cruz Biotechnology, Santa Cruz, CA, USA) in a 1:200 dilution and then anti-vascular endothe- lial growth factor (VEGF) (Santa Cruz Biotechnology) in a 1:500 dilution overnight at 4 C. The sections were then incu- bated with biotinylated secondary antibodies (1:1000) for 1 h. Following a washing step with PBS, streptavidin–horseradish peroxidase was applied. Finally, the sections were rinsed in PBS and developed with diaminobenzidine tetrahydrochloride substrate for 10 min. At least three random fields of each sec- tion were examined at 100 (Kim et al., 2014).