CREB1 and lung adenocarcinoma: Moreover, recent studies with lung adenocarcinoma xenografts have shown a significant stimulation of tumor progression in mice exposed to social stress, an effect associated with upregulation of nAChR subunits alpha7 and alpha4 and accompanied by systemic increase in stress neurotransmitters, reduction of GABA and activation of the cAMP/P-CREB/ERK pathway in tumor tissues [34].