ZFP42 (zinc finger protein 42) is a transcription factor that plays critical roles in stem cell maintenance, epigenetic regulation, and tissue-specific gene expression. ZFP42 functions as a DNA-binding transcriptional regulator that maintains stemness in human epidermal stem and progenitor cells through regulation of CRY1, linking circadian rhythms to stem cell functions 1. The protein exhibits positive autoregulation by binding to its own promoter region and activating transcription, though this regulation is lost in prostate cancer cells 2. ZFP42 belongs to the YY1 subfamily of C2H2 zinc finger transcription factors and is expressed in normal epithelial cells including keratinocytes, prostate epithelial cells, and lung epithelial cells, as well as some carcinoma cell lines 3. In male reproductive function, ZFP42 knockout mice display impaired testicular function, abnormal sperm morphology, and altered gene expression patterns 4. The protein also participates in epigenetic regulation through interaction with TET1, controlling DNA methylation patterns that influence ADCY3 expression and obesity susceptibility 5. Additionally, ZFP42 expression is upregulated in colorectal cancer through the CPNE7-NONO pathway, promoting tumor progression 6. These findings establish ZFP42 as a multifunctional transcription factor essential for stem cell biology, reproductive health, and metabolic regulation.