To examine the influence of Twist1 on tumor progression, LAP-tTA or LAP-tTA/TRE-Twist1/Luc mice were crossed with TRE-MYC (Shachaf et al., 2004) (Figure 1a) to generate transgenic mice that inducibly expressed MYC alone (MYC mice) or co-expressed MYC, Twist1 and luciferase (Luc) in a liver-specific manner (MYC/Twist1 mice) (Figure 1b). This evidence concerns the gene MYC and neoplasm.