As mitochondrial content is regulated by AMPK (O'Neill et al., 2013) and has emerged as an important factor regulating tumor progression (Hirschey et al., 2015), we measured components of the electron transport chain and found that they were also comparable between p53−/− AMPK β1+/+ and p53−/− AMPK β1−/− mice, suggesting that tumor mitochondrial content was not altered (Fig. S3A,F). Here, TP53 is linked to neoplasm.