TGFβ signalling: a complex web in cancer progression

The distortion of growth factor signalling is the most important prerequisite in tumour progression. Transforming growth factor-beta (TGF beta) signalling regulates tumour progression by a tumour cell-autonomous mechanism or through tumour-stroma interaction, and has either a tumour-suppressing or tumour-promoting function depending on cellular context. Such inherent complexity of TGF beta signalling results in arduous, but promising, assignments for developing therapeutic strategies against malignant tumours. As numerous cellular context-dependent factors tightly maintain the balance of TGF beta signalling and contribute to the regulation of TGF beta-induced cell responses, in this Review we discuss how they maintain the balance of TGF beta signalling and how their collapse leads to tumour progression.