Background/Aim: Casein kinase 1 epsilon (CK1 epsilon) is a member of the casein kinase 1 family, which includes highly conserved and ubiquitous serine/threonine protein kinases. Recent research has revealed that CK1 epsilon plays an important role in a variety of human cancer types; however, its role in human melanoma remains unclear. The aim of this study was to elucidate the clinical role of CK1 epsilon in patients with melanoma. Patients and Methods: Samples from 34 patients with melanoma were analyzed by immunohistochemical staining. Formalin-fixed paraffin-embedded tissue microarrays were also examined by two histopathologists to assess CK1 epsilon protein expression in humans. Results: Cytoplasmic CK1 epsilon protein expression was significantly lower in tumor tissue than in normal tissue. Lack of cytoplasmic CK1 epsilon protein was signficantly correlated with distant metastasis (p=0.022) and poorer survival (p=0.030). However, Kaplan-Meier survival analysis revealed that elevated expression of cytoplasmic CK1 epsilon protein was not significantly associated with the overall survival of patients with melanoma. Univariate and multivariate analyses demonstrated that lack of cytoplasmic CK1 epsilon protein expression was related to distant metastasis (p<0.001 and p=0.004), showing that CK1 epsilon was a prognostic factor. Conclusion: CK1 epsilon protein expression might serve as a prognostic indicator in the treatment of patients with melanoma.
