Published online Jul 6, 2019. doi: 10.12998/wjcc.v7.i13.1554
Peer-review started: January 7, 2019
First decision: February 13, 2019
Revised: April 4, 2019
Accepted: May 2, 2019
Article in press: May 2, 2019
Published online: July 6, 2019
Processing time: 180 Days and 23.2 Hours
Several studies have largely focused on the significant role of the nervous and immune systems in the process of tumorigenesis, including tumor growth, proliferation, apoptosis, and metastasis. The brain-gut-axis is a new paradigm in neuroscience, which describes the biochemical signaling between the gastrointestinal (GI) tract and the central nervous system. This axis may play a critical role in the tumorigenesis and development of GI cancers. Mechanistically, the bidirectional signal transmission of the brain-gut-axis is complex and remains to be elucidated. In this article, we review the current findings concerning the relationship between the brain-gut axis and GI cancer cells, focusing on the significant role of the brain-gut axis in the processes of tumor proliferation, invasion, apoptosis, autophagy, and metastasis. It appears that the brain might modulate GI cancer by two pathways: the anatomical nerve pathway and the neuroendocrine route. The simulation and inactivation of the central nervous, sympathetic, and parasympathetic nervous systems, or changes in the innervation of the GI tract might contribute to a higher incidence of GI cancers. In addition, neurotransmitters and neurotrophic factors can produce stimulatory or inhibitory effects in the progression of GI cancers. Insights into these mechanisms may lead to the discovery of potential prognostic and therapeutic targets.
Core tip: Although studies have revealed the role of the brain-gut axis in cancer, the bidirectional signal transmission of the brain-gut axis remains unclear. This review summarizes current findings concerning the relationship between the brain-gut axis and gastrointestinal (GI) cancer and focuses on the significant role of the brain-gut axis in tumorigenesis and cancer progression, including tumor proliferation, invasion, apoptosis, autophagy, and metastasis. The central nervous, sympathetic, and parasympathetic nervous systems, neurotransmitters, and neuropeptides may regulate the malignant tumor phenotype in GI cancers. An insight into these mechanisms may lead to the discovery of potential prognostic markers and new targets for GI cancer therapy.