Objective To explore the expression and clinical significance of thymidine kinase 1 (TK1) in prostate cancer using bioinformatic approaches.

Methods Prostate cancer transcriptomic data from TCGA database were used to evaluate the prognostic value and biological relevance of TK1 in prostate cancer. Patients were stratified into high- and low-TK1 expression groups based on the median expression level of TK1. Differentially expressed genes between the two groups were identified, followed by functional enrichment analysis. The association between TK1 expression and tumor-infiltrating immune cells as well as response to immunotherapy was also assessed.

Results The overall survival (OS) in the high-TK1 expression group was (2.77±0.19) years, which was significantly lower than that in the low-TK1 expression group(3.20±0.24) years; P=0.017. Similarly, progression-free survival (PFS) was shorter in the high-TK1 group(2.65±0.17) yearscompared with the low-TK1 group(3.13±0.27) years; P < 0.001. Genes associated with TK1 were primarily enriched in pathways related to chromosome segregation, mitosis, and the cell cycle. Infiltration levels of activated memory CD4⁺ T cells and M1 macrophages were significantly higher in the high-TK1 group than in the low-TK1 group (P < 0.05). Patients with high TK1 expression exhibited lower immunophenotype scores (IPS).

Conclusion TK1 may influence the progression of prostate cancer by modulating the tumor microenvironment. TK1 may serve as a potential biomarker and therapeutic target for the prognosis of prostate cancer.