Fig. 1.

Interconnected networks of CEA and TGF-β signaling in cancer. The cancer cell is an autocrine source of CEA as well as of TGF-β which bind to their specific receptors, CEAR or TGF-β-RI:RII, respectively; the latter signaling via the NFκB pathway. Recently, it has been recognized that CEA also signals via TGF-β-R and initiates the same biological effects [26]. Additionally, Tregs and Bregs, as well as stroma cells, participate in this network by secreting TGF-β. It remains open whether the reverse is the case, and TGF-β may also interfere with the CEAR pathway, which is much less defined