Gemcitabine treatment stabilizes mutant p53 in the nuclei and induces the expression of mutant p53 target genes CdK1 (cyclin-dependent kinase 1) and CCNB1 (G2/mitotic-specific cyclin-B1), which are both involved in mitosis and therefore cell proliferation, leading to gemcitabine resistance in pancreatic cancer cells. Here, CCNB1 is linked to familial pancreatic carcinoma.