EGR1 and cancer: On transcriptional level, it can be positively regulated by a wealth of transcription factors, such as early growth response protein 1 (EGFR-1), peroxisome proliferator activated receptor γ (PPAR-γ), and tumor protein 53 (Tp53), which can directly bind to PTEN promoter region, while other transcription factors show the negative regulation of PTEN in several cancer models, such as mitogen activated protein kinase kinase-4 (MKK4), transforming growth factor β (TGF-β), and the polycomb group (PcG) protein BMI1 (Bermudez Brito et al., 2015).