We have characterized the phenotype of the stromal cells in three mouse models of PCa – a probasin-driven MYC (PB-MYC) model, a conditional ERG and PTEN genetic model (ERG/PTEN) and a transgenic adenocarcinoma mouse prostate (TRAMP) model – and found that the proportions of cells with a SM- or fibroblast-like character were distinct in each of the three models. The gene discussed is ERG; the disease is adenocarcinoma.