The PRF FOXO1 (fork head frame transcription factor O1), also known as FKHR, plays an important role in cell proliferation and cancer biology (Kim et al., 2018) and its aberrant expression is associated with the occurrence of a variety of tumors (Shi et al., 2018); over-expression is associated with rhabdomyosarcoma (Ryder et al., 2017), breast cancer (Yu et al., 2019), and ovarian cancer (Han et al., 2019), and low expression is associated with colon cancer (Chae et al., 2019) and prostate cancer (Zhang et al., 2011). Here, FOXO1 is linked to breast cancer.