Immune Microenvironment and the Effect of Vascular Endothelial Growth Factor Inhibition in Hepatocellular Carcinoma.

Systemic therapy for unresectable hepatocellular carcinoma (HCC) has progressed with the development of multiple kinases, such as vascular endothelial growth factor (VEGF) signaling, targeting cancer growth and angiogenesis. Additionally, the efficacy of sorafenib, regorafenib, lenvatinib, ramucirumab, and cabozantinib has been demonstrated in various clinical trials, and they are now widely used in clinical practice. Furthermore, the development of effective immune checkpoint inhibitors has progressed in systemic therapy for unresectable HCC, and atezolizumab + bevacizumab (atezo/bev) therapy and durvalumab + tremelimumab therapy are now recommended as first-line treatment. Atezo/bev therapy, which combines an anti-programmed cell death 1 ligand 1 antibody with an anti-VEGF antibody, is the first cancer immunotherapy to demonstrate efficacy against unresectable HCC. With the increasing popularity of these treatments, VEGF inhibition is attracting attention from the perspective of its anti-angiogenic effects and impact on the cancer-immune cycle. In this review, we outline the role of VEGF in the tumor immune microenvironment and cancer immune cycle in HCC and outline the potential immune regulatory mechanisms of VEGF. Furthermore, we consider the potential significance of the dual inhibition of angiogenesis and immune-related molecules by VEGF, and ultimately aim to clarify the latest treatment strategies that maximizes efficacy.