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‑β (TGF‑β) 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‑β signaling pathway, TGF‑β1 and TGF‑β receptor 1 (TGF‑βR1), 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‑β1 and TGF‑βR1 promote proliferation, migration and epithelial‑mesenchymal transition of tumor cells by activating other signaling pathways, signaling molecules or microRNAs (miRs), such as the NF‑κB signaling pathway and miR‑133b. In addition, some inhibitors targeting TGF‑β1 and TGF‑βR1 have exhibited positive effects in experiments. The present review discusses the association between TGF‑β1 or TGF‑βR1 and tumors, and the development of some inhibitors, hoping to provide more approaches to help identify novel tumor markers to restrain and cure tumors.