Activation of K-ras in virtually all samples of ductal pancreatic adenocarcinoma marks the initiation of the multistep transformation process, but functional inactivation of p16INK4a in up to 90% of cases ranks second in frequency (Caldas et al, 1994; Hezel et al, 2006). This evidence concerns the gene CDKN2A and pancreatic ductal adenocarcinoma.