SIRT1 and osteosarcoma: These findings were corroborated upon ectopic expression of MYC-SIRT1 and FLAG-FOXA2 in human osteosarcoma U2OS cells (which do not express FOXA2 endogenously), as we found a specific interaction of FLAG-FOXA2 and MYC-SIRT1 by using FLAG- and SIRT1-specific antibodies (data not shown).