TK1 and cancer: In hepatocellular carcinoma (HCC), YBX1 modulates the expression of nucleotide metabolic enzymes Ribonucleotide Reductase M2 (RRM2), Thymidine Kinase 1 (TK1), and Thymidylate Synthase (TYMS), leading to increased nucleotide metabolism and DNA synthesis, which are essential for cancer cell proliferation [92].