Figure 1.

(A) C/EBPδ expression is restricted to hypoxic tumour areas and increases mTOR stability through repression of FBXW7. C/EBPδ acts as a tumour suppressor through various mechanisms leading to decreased primary tumour formation. Balamurugan et al now propose that C/EBPδ acts through HIF-1α stabilization to promote metastasis formation. This effect is dependent on repression of FBXW7, which leads to increased mTOR and HIF-1α. (B) C/EBPδ parallels TGFβ effects on tumorigenesis. C/EBPδ has also been shown by Bengoechea-Alonso et al to influence TGFβ signalling, although in the latter case the directionality of the effect in this context is unclear. FBXW7 also controls levels of CEBPα, and may mediate crosstalk between these transcription factors.