KRAS and sarcoma: As shRNA mediated silencing of Kras (G12v)-IRES-GFP, the driver oncogene used to initiate the mouse sarcomas, markedly inhibits the growth of Kras;p16p19nullsarcoma cells (Figure 2A–B, Figure 2—figure supplement 1A–B), shRNAs directed against either GFP or KRAS served as positive controls in this screen and showed clear growth-inhibitory effects (Figure 1C–D, 1H-I).