Role and clinical significance of TGF-β1 and TGF-βR1 in malignant tumors (Review)

The appearance and growth of malignant tumors is a complicated process that is regulated by a number of genes. In recent years, studies have revealed that the transforming growth factor-beta (TGF-beta) signaling pathway serves an important role in cell cycle regulation, growth and development, differentiation, extracellular matrix synthesis and immune response. Notably, two members of the TGF-beta signaling pathway, TGF-beta 1 and TGF-beta receptor 1 (TGF-beta R1), are highly expressed in a variety of tumors, such as breast cancer, colon cancer, gastric cancer and hepatocellular carcinoma. Moreover, an increasing number of studies have demonstrated that TGF-beta 1 and TGF-beta R1 promote proliferation, migration and epithelial-mesenchymal transition of tumor cells by activating other signaling pathways, signaling molecules or microRNAs (miRs), such as the NF-kappa B signaling pathway and miR-133b. In addition, some inhibitors targeting TGF-beta 1 and TGF-beta R1 have exhibited positive effects in in vitro experiments. The present review discusses the association between TGF-beta 1 or TGF-beta R1 and tumors, and the development of some inhibitors, hoping to provide more approaches to help identify novel tumor markers to restrain and cure tumors.