Decreased CK1δ expression predicts prolonged survival in colorectal cancer patients

Cancers arising from the large intestine or rectum are called colorectal cancer (CRC) and represent the fourth leading cause of cancer-related death worldwide. Since casein kinase 1 (CK1) isoforms are involved in many cellular processes and have been reported to be deregulated in various tumor entities, CK1 has become an interesting drug target. In this study, we examined the potential of CK1 delta expression levels in tumor tissue of CRC patients as a prognostic biomarker. We show by quantitative RNA expression analyses that decreased CK1 delta expression levels in tumor tissue predict prolonged survival rates. Random sampling of CK1 delta stained tumor tissue indicates that CK1 delta gene expression corresponds with CK1 delta protein expression. Especially in low grade (grade 1, grade 2) and in UICC II/III classified tumors decreased CK1 delta RNA levels correlate with significantly improved survival rates when the tumor was located in the right colon. We furthermore found gender-specific differences within these subgroups, revealing most significant increase in overall survival rates in male patients with tumors in right colon expressing low levels of CK1 delta RNA. Results become even clearer, when only male patients over 50 years were considered. Together, these findings support the assumption that CK1 delta might be a prognostic biomarker for CRC thereby providing an interesting drug target for the development of new therapy concepts.