CMPK1 (cytidine/uridine monophosphate kinase 1) is a pyrimidine nucleotide kinase that catalyzes the phosphorylation of UMP and CMP to their diphosphate forms using ATP, playing a crucial role in de novo pyrimidine nucleotide biosynthesis 1. The enzyme exhibits both cytoplasmic and nuclear localization, with nuclear expression serving as a prognostic marker in cancer 2. CMPK1 can be allosterically regulated by compounds like doxorubicin, which binds with a Kd of 1216 nM and activates phosphorylation of CMP, dCMP, and UMP 1. In pathological contexts, CMPK1 contributes to immune-metabolic dysfunction in acute kidney injury through monocyte-specific upregulation, leading to mitochondrial damage, pyroptosis, and pro-inflammatory responses 3. The gene shows significant clinical relevance across multiple diseases: genetic variants associate with corneal curvature in Asian populations 4, nuclear expression predicts poor prognosis in triple-negative breast cancer independently of other factors 2, and polymorphisms influence survival outcomes in non-small cell lung cancer patients receiving gemcitabine therapy 5. CMPK1 is also regulated by microRNAs in hepatitis B and ovarian cancer, highlighting its importance in disease pathogenesis 67.