CDK1 and cholangiocarcinoma: As discovered by Yamamura et al., phosphorylated CDK1 (p-CDK1), p-CDK2, cyclin B1, and cyclin E1 levels increase within cholangiocarcinoma tissues; in addition, p-CDK1 and cyclin B1 nuclear levels positively correlate with the clinical stage and with lymph node metastasis, while the expression of p-CDK 1 is related to poor patient survival [21].