PTEN and neoplasm: To assess the tumor incidence, latency and spectrum of Pten-deficient adult mice, we utilize two mouse strains: firstly, the ROSA26 Cre-estrogen receptor (R26-CreERT) knock-in mouse line, which expresses inducible Cre recombinase driven by the ubiquitous promoter ROSA26[27] and secondly, the Ptenfx/fx mouse carrying loxP-flanked exon 5 encoding the phosphatase domain of PTEN [28], [29].