A novel cell-penetrating FOXM1-inhibiting p19 tumor suppressor ARF-derived peptide with some D-amino acids to improve its efficiency (p19ARF 26–44 peptide) has been used effectively in treatment of mouse hepatocellular carcinoma and acute lymphoblastic leukemia in vitro and in vivo [79, 80], and in breast cancer studies [38]. This evidence concerns the gene CDKN2A and breast cancer.