CREB1 and breast carcinoma: However, the expression of CREM transcript variant 2, which harbors the N-terminal domain of CREM but lacks the bZIP domain (CREMΔZIP) and is predicted to compete with CREB family members for necessary transcriptional cofactors (Fig. 8B), was significantly increased in breast cancer, lung adenocarcinoma, and lung squamous cell carcinoma having low TTP expression (Fig. 8C).