PTEN and cancer: Furthermore, we mimicked the activation of the MAPK signaling pathway (aberrantly activated in ~50% of HCCs46) using constitutive expression of the proto-oncogene Ras. In light of the evident differences in MAPK activation states and cancer malignant features incumbered by distinct Ras isoforms and point mutations in several cancers50–54, including HCCs28,41,55, we employed distinct oncogenic mutations of Nras: NrasG12D (pT3-NrasG12D-GFP) and NrasG12V (pT/CaggsNrasG12V-IRES-Luc), to generate two additional HCC models, both combined with Pten loss.