HIC2 (HIC ZBTB transcriptional repressor 2) is a zinc finger transcriptional regulator with dual roles in developmental and disease contexts. Primary function: HIC2 acts as a transcriptional repressor that controls developmental hemoglobin switching by repressing BCL11A transcription in erythroid cells 1. During fetal development, HIC2 is highly expressed and inhibits BCL11A through direct binding to erythroid enhancers, reducing chr22 accessibility and GATA1 binding 1. This HIC2-mediated repression is developmentally downregulated by let-7 miRNAs in adult cells, allowing BCL11A reactivation and fetal hemoglobin silencing 2. Mechanism: HIC2 functions through direct DNA binding and protein-protein interactions. In hemoglobin switching, it causes steric hindrance of transcription factor GATA1 binding 1. Notably, HIC2 exhibits opposing functions to its homolog HIC1: while HIC1 represses SIRT1, HIC2 activates SIRT1 transcription, potentially protecting cardiac tissue from ischemia-reperfusion injury 3. Disease relevance: HIC2 functions as a tumor suppressor in glioma and glioblastoma. It is hypermethylated and downregulated in these malignancies, predicting poor prognosis 4. HIC2 suppresses glioblastoma progression by transcriptionally repressing SEMA3A and attenuating TGF-β signaling 5. HIC2 also participates in bladder cancer chemoresistance regulation through miRNA-mediated mechanisms 6. Clinical significance: HIC2 represents a therapeutic target for hemoglobinopathies and brain tumors, with potential applications in personalized cancer therapy and cardiac protection.