Considering that GS25 is a natural MDM2 inhibitor that can exert its anticancer activity in a p53-independent manner, three prostate cancer cell lines with different p53 backgrounds were selected for this study, i.e. LNCaP (p53 wild-type), DU145 (p53 mutant), and PC3 (p53 null). This evidence concerns the gene MDM2 and prostate carcinoma.