FOXO4 and cancer: In addition, members of the FOXO family, such as FOXO1, FOXO3, FOXO4, and FOXO6 (Jacobs et al, 2003), have been found to participate in various physiological responses, such as DNA damage (Tran et al, 2002), caloric restriction (Carrano et al, 2009) and oxidative stress (Essers et al, 2005), and play crucial roles in cancer initiation, progression, and chemo‐resistance.