In the TRAMP (Transgenic adenocarcinoma of mouse prostate) model, genetic ablation of the tetraspanins Cd9 and Cd151 did not affect prostate tumor initiation but Cd151 ablation reduces spontaneous metastatic spread whereas ablation of the tetraspanin Cd9 increases spontaneous metastases, in an organ specific manner in both cases (Copeland et al., 2013a,b). This evidence concerns the gene CD9 and medical procedure.