AUTHOR=Luo Kai-Jun , Chen Chang-Xu , Yang Jia-Peng , Huang Yun-Chao , Cardenas Eduardo R. , Jiang Jean X. TITLE=Connexins in Lung Cancer and Brain Metastasis JOURNAL=Frontiers in Oncology VOLUME=Volume 10 - 2020 YEAR=2020 URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2020.599383 DOI=10.3389/fonc.2020.599383 ISSN=2234-943X ABSTRACT=Connexins (Cxs) are associated with brain metastasis of lung cancer cells. Thus, it is necessary to determine whether gap-junction-forming Cxs are involved in communication between lung cancer cells and host cells, such as the endothelial cells forming the brain-blood-barrier and cells in the central nervous system. Data from multiple studies support Cxs as tumor suppressors during lung cancer occurrence. However, recently, evidence suggests that during cancer metastasis to the brain, cancer cells may establish communication with host cells in a gap-junction-dependent or independent manner. The current review discusses gap junction studies in lung cancer development and brain metastasis, highlighting important unanswered questions and controversies.