Of these three genes, only Ptf1a is indispensable for acinar cell differentiation (Krapp et al., 1998; Pin et al., 2001; Kawaguchi et al., 2002; Holmstrom et al., 2011; von Figura et al., 2014b), and it will be of interest to determine the relative rank of these factors as suppressors of cancer initiation and progression, and their epistatic relationship. This evidence concerns the gene PTF1A and cancer.