TYMS and neoplasm: Within the tumor microenvironment, specific enzymes are overexpressed due to tumor heterogeneity, genetic mutations, and cell proliferation.[70, 71] Tumor cells interact with surrounding cells via cytokines and growth factors, leading to the upregulation of enzymes such as matrix metalloproteinases, tyrosine kinases, cyclooxygenases, acid hydrolases, telomerase, and thymidylate synthase, etc. These enzymes critically influence tumor growth, invasion, metastasis, and treatment outcomes.[72] Moreover, tumor hypoxia and inflammatory conditions further induce enzyme expression.