SP3 is a ubiquitously expressed transcription factor that binds to GC box and GT box promoter elements through its three conserved Cys2His2 zinc fingers 1. SP3 can function as either a transcriptional activator or repressor depending on cellular context and post-translational modifications 1. Unlike SP1, SP3 often acts as a weaker activator or competitive inhibitor. SP3 positively regulates several genes including leukotriene C4 synthase in monocytes 2, extracellular superoxide dismutase in lung fibroblasts 3, and hyaluronan synthase 2 4. However, SP3 can also function as a transcriptional repressor, as demonstrated in CYP2F1 gene regulation where SP3 antagonizes SP1-mediated activation 5 and in dopamine D1A receptor gene regulation where SP3 represses SP1-induced transcription 6. Recent studies show SP3 cooperates with ELK4 and SP1 in a noncanonical manner to regulate oncogenic pathways in colorectal cancer 7. The balance between SP1 and SP3 levels appears critical for tissue-specific gene expression, with their relative concentrations varying between organs such as lung and liver 5. This regulatory mechanism makes SP3 an important modulator of cell-cycle regulation, hormone responses, and housekeeping gene expression.