KRAS and neoplasm: For instance, EGFR ablation prevents tumour development in the background of Cdkn2a deletion, but only delays it when p53 is lost (Navas et al., 2012), and erlotinib in Kras; Tgfbr2flox; Cre mice increases survival in combination with gemcitabine, as described above (Miyabayashi et al., 2013).