Growth Hormone and the Epithelial-to-Mesenchymal Transition.

Context: Previous studies have implicated growth hormone (GH) in the progression of several cancers, including breast, colorectal, and pancreatic. A mechanism by which GH may play this role in cancer is through the induction of the epithelial-to-mesenchymal transition (EMT). During the EMT process, epithelial cells lose their defining phenotypes, causing loss of cellular adhesion and increased cell migration. This review aims to carefully summarize the previous two decades of research that points to GH as an initiator of EMT, in both cancerous and noncancerous tissues. Evidence Acquisition: Sources were collected using PubMed and Google Scholar search engines by using specific GH- and/or EMT-related terms. Identified manuscripts were selected for further analysis based on presentation of GH-induced molecular markers of the EMT process in vivo or in vitro. Evidence Synthesis: Cellular mechanisms involved in GH-induced EMT are the focus of this review, both in cancerous and noncancerous epithelial cells. Conclusions: Our findings suggest that a myriad of molecular mechanisms are induced by GH that cause EMT and may point to potential therapeutic use of GH antagonists or any downregulator of GH action in EMT-related disease.