Cell cycle-related kinase in carcinogenesis.

Cell cycle-related kinase (CCRK) is a novel protein kinase homologous to both cyclin-dependent kinase 7 (Cdk7) and Cak1p groups of CDK-activating kinase (CAK). CCRK activates Cdk2, which controls the cell-cycle progression by phosphorylating a threonine residue conserved in Cdk2. Previous studies have indicated that the CCRK protein levels were elevated by more than 1.5-fold in tumor tissue, and that the overexpression of CCRK is associated with poor prognosis of the patients. Moreover, recent studies have shown that CCRK is involved in the Wnt signaling pathway associated with the genesis and evolution of cancer. This review aims to systematically present the information currently available on CCRK obtained from in vitro and in vivo studies and highlight its significance to tumorigenesis.