Int J Biol Sci 2018; 14(2):111-123. doi:10.7150/ijbs.23230 This issue
1. Faculty of Health Sciences, University of Macau, Macau SAR, China;
2. Department of Oncology, The Affiliated Hospital of Southwest Medical University, Luzhou, China.
3. Center for Translational Research, Department of Surgery and GW Cancer Center, George Washington University, Washington DC, USA.
Transforming growth factor β (TGF-β) signaling pathway plays important roles in many biological processes, including cell growth, differentiation, apoptosis, migration, as well as cancer initiation and progression. SMAD4, which serves as the central mediator of TGF-β signaling, is specifically inactivated in over half of pancreatic duct adenocarcinoma, and varying degrees in many other types of cancers. In the past two decades, multiple studies have revealed that SMAD4 loss on its own does not initiate tumor formation, but can promote tumor progression initiated by other genes, such as KRAS activation in pancreatic duct adenocarcinoma and APC inactivation in colorectal cancer. In other cases, such as skin cancer, loss of SMAD4 plays an important initiating role by disrupting DNA damage response and repair mechanisms and enhance genomic instability, suggesting its distinct roles in different types of tumors. This review lists SMAD4 mutations in various types of cancer and summarizes recent advances on SMAD4 with focuses on the function, signaling pathway, and the possibility of SMAD4 as a prognostic indicator.
Keywords: TGF-β, SMAD4, tumorigenesis, prognosis, mouse model