ESF1 (Eighteen S rRNA factor 1) is a nucleolar protein with dual roles in ribosome biogenesis and cancer regulation. In ribosome biogenesis, ESF1 associates with pre-40S ribosomal particles and facilitates early-stage pre-rRNA processing by helping pre-rRNA acquire conformations favorable for cleavage, rather than directly catalyzing cleavage events 1. Beyond its nucleolar function, ESF1 plays a critical oncogenic role by positively regulating MDM2 protein stability through inhibition of ubiquitination, thereby suppressing p53-mediated apoptosis and promoting cell proliferation and tumorigenesis 2. Elevated ESF1 expression correlates with poor survival in multiple cancers, including pancreatic and gastric cancers 23. ESF1 has emerged as a candidate biomarker for hepatocellular carcinoma recurrence prediction 4 and as a disease-associated gene in idiopathic pulmonary arterial hypertension 5. Additionally, ESF1 was identified as a candidate gene near an epileptogenesis susceptibility locus in seizure models 6. The protein's essential role in both fundamental cellular processes (ribosome biogenesis) and cancer progression positions it as an important target for understanding tumorigenesis mechanisms and potential therapeutic intervention in multiple malignancies.