CDKN1B and pancreatic adenocarcinoma: The cell lines tested, PANC-1 and Capan-1, harbour mutations in the tumour suppressors TP53, CDKN2A, CDKN2B and CDKN1B encoding for p53, p14ARF and p16INK4A, p15INK4B and p27Kip1, key constituent proteins encompassing all three arms of the origin activation checkpoint and representing mutations commonly found in pancreatic adenocarcinoma (Figure 1).