Rather, they progress through tumor development in a manner more similar to human GBM.30 GEMMs also allow investigators to directly evaluate how mutations in specific genes (like PTEN or P53) can impact sensitivity to treatment.48 For example, Lin et al. used p53;p16Ink4a/p19Arf;K-Rasv12;LucR and a Pten;p16Ink4a/p19Arf;K-Rasv12;LucR (p53 or PTEN loss with concomitant p16 loss, p19 loss, and K-Ras expression) models to investigate the treatment response to a PARP inhibitor ABT-888 combined with TMZ. Here, PTEN is linked to glioblastoma.