CPSF1 (cleavage and polyadenylation specific factor 1) is a core component of the cleavage and polyadenylation specificity factor (CPSF) complex that mediates pre-mRNA 3'-end formation by recognizing AAUAAA signal sequences and facilitating cleavage and poly(A) addition 1. Beyond its canonical role in mRNA processing, CPSF1 functions as an E3 ubiquitin ligase that regulates protein stability; ABL kinases compete with CPSF1 for binding to CUL4A, protecting oncogenic transcription factors HIF-1α and MYC from CPSF1-mediated degradation 2. CPSF1 is upregulated in advanced prostate cancer, where it suppresses intergenic polyadenylation sites to promote glycolytic gene expression, and its knockdown selectively inhibits cancer cell growth 3. Loss-of-function CPSF1 mutations cause early-onset high myopia (eoHM), with zebrafish models demonstrating abnormal retinal ganglion cell axon projection toward the tectum 4. CPSF1 downregulation also occurs in diabetic retinopathy, where its restoration via gene therapy alleviates vascular endothelial cell apoptosis through MAPK/ERK pathway suppression 5. Dysregulation of CPSF1 contributes to head and neck squamous cell carcinoma through aberrant alternative splicing 6, establishing CPSF1 as a multifunctional protein relevant to ocular development, cancer pathobiology, and metabolic disease.