Figure 9. Co-localization of Senescence-Associated beta-galactosidase (SA-β-gal) activity and lipofuscin depiction in fresh-frozen tissue sample of benign prostatic hyperplasia (BPH) pretreated with SA-β-gal and subsequently embedded in paraffin. Fresh samples with BPH were snap frozen, fixed in 4% formaldehyde, washed with buffer, incubated in SA-β-gal solution (turquoise color), subsequently fixed with formal-dehyde, and then embedded in paraffin, as previously shown (Michaloglou et al 2005). Sections where then double stained with Sudan Black B (SBB) (dark blue-black granules) and Nuclear Fast Red (NFR) as counterstain. Areas with the characteristic pathology of BPH showed SA-β-gal activity and lipofuscin positivity. Note the weak intensity of the Sa-β-gal staining.