E2F8 is an atypical E2F transcription factor with dual roles as both transcriptional repressor and activator, functioning primarily as a negative regulator of the classical E2F family. As a repressor, E2F8 binds E2 recognition sites independently of DP proteins and suppresses E2F1-E2F3 expression, creating a feedback loop that prevents p53-dependent apoptosis during S phase 1. E2F8 regulates polyploidization in specialized cells by repressing cytokinesis-promoting genes, particularly in placental trophoblasts and hepatocytes, where it is essential for normal development 2. Conversely, E2F8 functions as a transcriptional activator in angiogenesis by binding VEGFA promoters and activating VEGF expression in collaboration with HIF1A 3. In cancer pathogenesis, E2F8 predominantly exhibits oncogenic properties. E2F8 is significantly upregulated in hepatocellular carcinoma, correlating with advanced disease stage and poor survival outcomes, with elevated expression being an independent risk factor 4. In lung adenocarcinoma, E2F8 transcriptionally activates RRM2, promoting DNA synthesis and cell cycle progression; combining E2F8 knockdown with WEE1 inhibition shows synergistic anti-tumor effects 5. E2F8 overexpression promotes breast cancer cell growth, DNA repair capacity, and chemoresistance through YTHDF1-mediated mRNA stabilization 6. However, E2F8 also displays context-dependent tumor-suppressive functions, exemplified by its role as a repressor of IL-9 in systemic sclerosis pathogenesis 7, indicating complex cell-type and pathway-specific functions.