APOBEC3C is a cytidine deaminase that functions primarily as an antiviral defense mechanism by deaminating cytosine residues in single-stranded DNA 1. The protein exhibits unique sequence preferences and produces strand-coordinated mutation clusters, particularly enriched near transcription start sites of active genes, distinguishing it from other APOBEC3 family members 2. In viral infections, APOBEC3C contributes to HIV-1 restriction through specific interactions with viral Vif protein, though it remains susceptible to Vif-mediated degradation 1. During persistent Epstein-Barr virus infection, APOBEC3C expression increases and localizes to mitochondria, inducing C-to-T mutations in mitochondrial DNA and reducing mitochondrial copy number 3. In cancer contexts, APOBEC3C displays complex roles: it promotes DNA replication stress resistance in pancreatic cancer cells following gemcitabine treatment 4, while serving as a tumor suppressor in prostate cancer where its expression is repressed by androgen receptor signaling 5. Conversely, in gliomas, APOBEC3C functions as an oncogene, promoting cell proliferation, migration, and invasion while activating NF-κB signaling pathways and facilitating M2-type macrophage polarization 67. These diverse functions highlight APOBEC3C's context-dependent roles in cellular defense and oncogenesis.