HIF1A and neoplasm: Oxidative stress can activate a variety of transcription factors including NF-κB, AP-1, p53 (the gene that codes for a protein that regulates the cell cycle and hence functions as a tumour suppressor), hypoxia-inducible factor 1-alpha (HIF-1α), peroxisome proliferator-activated receptor gamma (PPAR-γ), β-catenin/Wnt (regulates stem cell pluripotency and cell fate decisions during development), and Nrf2 (basic leucine zipper (bZIP) protein which regulates the expression of antioxidant proteins that protect against oxidative damage initiated by injury and inflammation).