CALCA and cancer: We found that KC-OSKM mice given Dox for 1–2 weeks often developed undifferentiated cancers in the stomach (Fig. 6b and Supplementary Table 1), which is consistent with the observation that Cre-LoxP recombination also occurs in the pyloric glands of the stomach with Pdx1-ires-Cre allele (Supplementary Fig. 1B, C).