We found both of EZH2 and H2K27me3 were evidently elevated like P21 and P27 in seminal vesicles of TRAMP mice from 24 weeks of age, while STAT3 and its phosphorylated form p-STAT3 was overexpressed, which suggested that STAT3-EZH2 might confer a significant improvement in seminal vesicle tumor cell proliferation of TRAMP mice, and further demonstrated anti-tumor activities of P53, P21 and P27 were lost in seminal vesicles of TRAMP mice. This evidence concerns the gene TP53 and neoplasm.