Different mouse strains were injected intraveneously with ecotropic MuLE lentiviruses expressing combinations of shRNA against Cdkn2a, Trp53, Tsc2 and Pten with or without expression of HrasG12V, PIK3CAH1047R or Myc. Tumour development was monitored by in vivo imaging. The gene discussed is MYC; the disease is neoplasm.