ID1 and osteosarcoma: Of the 3 transcription factors found to be over-expressed in SW-DKK3 cells (ID1, JUN and FOXO1), FOXO1 secured our immediate attention for 3 primary reasons: (1) FOXO1 is known to promote functional differentiation of myofibroblasts [47], (2) FOXO1 inhibits osteosarcoma malignancy via WNT inhibition [48], and (3) FOXO1 transcription has been suggested in response to steroid hormones [49].