DCK is a promising prognostic biomarker and correlated with immune infiltrates in hepatocellular carcinoma

BACKGROUND: Deoxycytidine kinase (DCK), an enzyme in the nucleoside biosynthetic pathway, can affect the development of immune cells. However, the relationships between the expression of DCK, patient prognosis, and tumor-infiltrating immune cells (TIICs) in hepatocellular carcinoma (HCC) are still unclear. METHODS: The expression of DCK in HCC was analyzed through the Oncomine and Tumor Immune Estimation Resource (TIMER) databases. The impact of DCK on clinical prognosis was investigated via the Kaplan-Meier plotter and verified in the Gene Expression Profiling Interactive Analysis (GEPIA) databases. The interrelationships between DCK expression and TIICs in HCC were analyzed by the TIMER database. Additionally, the relationship between DCK expression and immune cell gene markers was calculated through TIMER and GEPIA databases. RESULTS: Compared with the adjacent normal tissues, high expression of DCK was observed in HCC tissues. Also, the higher expression of DCK was correlated to poorer prognosis in HCC patients, and it was associated with decreased survival in those with early stage and grade. Moreover, DCK expression was positively correlated with TIICs, including CD4(+) and CD8(+) T cells, B cells, monocytes, tumor-associated macrophages (TAMs), M1 and M2 macrophages, neutrophils, natural killer cells, and dendritic cells. Specifically, DCK expression levels were significantly associated with diverse immune gene marker sets, including those of Tregs and exhausted T cells. CONCLUSION: These findings suggest that DCK expression is correlated with patient outcomes and tumor infiltration cell levels in HCC patients. Additionally, the increased level of DCK was associated with marker genes of Tregs and exhaustion-related inhibitory receptors, suggesting the potential role of DCK in immunosuppression and immune escape. These findings suggest that DCK can function as a potential novel prognostic biomarker and reflect the immune infiltration status in HCC patients.