Mnt (Max binding protein), also known as MAD6, ROX, bHLHd3 (class D basic helix-loop-helix protein 3) or MXD6, is a 582 amino acid nuclear protein that forms a complex with Max (Myc-associated factor X) to repress transcription. Mnt contains one basic helix-loop-helix (bHLH) domain and is encoded by a gene that maps to human chromosome 17p13.3. Chromosome 17 comprises over 2.5% of the human genome and encodes over 1,200 genes. Two key tumor suppressor genes are associated with chromosome 17, namely, p53 and BRCA1. Tumor suppressor p53 is necessary for maintenance of cellular genetic integrity by moderating cell fate through DNA repair versus cell death. Malfunction or loss of p53 expression is associated with malignant cell growth and Li-Fraumeni syndrome.