This notion is supported with in vitro evidence that Skp2 deficiency reduces cell proliferation, transformation and migration of Pten/Trp53 double null MEFs (Figure 1), and with in vivo evidence that SKP2 deficiency constrains the initiation and growth of prostate tumors of Ptenpc−/−; Trp53pc−/− mice (Figure 1 and Supplementary Figure S1). The gene discussed is PTEN; the disease is prostate neoplasm.