Helios protein (encoded by the IKZF2 gene) is a member of the Ikaros family of transcription factors and contains multiple zinc finger domains that facilitate DNA binding and the formation of homodimers or heterodimers. It is predominantly expressed in T cells, regulatory T cells (Tregs), certain B cell subsets, and hematopoietic and epithelial tissues. Helios plays a crucial role in T cell activation, proliferation, and the stability and function of Tregs. Additionally, Helios has been identified as a potential biomarker in autoimmune diseases and may influence tumor development by regulating gene expression and modulating cell differentiation and proliferation.