Recently, Gu et al. showed that a combined treatment of Pmp53, a plasmid containing both MDM2 small hairpin RNA and the wild type p53 gene, with zinc could markedly inhibit tumor growth through increasing p21 expression and inducing G1 arrest in tumor xenografts of PC-3 cells, as compared to the treatment group with only Pmp53 [83]. Here, MDM2 is linked to neoplasm.