Immune checkpoint molecules signal regulatory protein alpha in the development of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a primary malignant tumor of the liver and one of the most common malignant tumors, as well as the third leading cause of cancer-related death. In recent years, immune checkpoint inhibitors have emerged as a key strategy in cancer treatment. However, anti-programmed cell death 1/programmed death ligand 1 therapies, one of the main immunotherapeutic approaches, only elicit a response in only approximately 20% of advanced HCC. This suggests that there may be other immune checkpoints playing important roles in HCC immunotherapy. Recent studies have highlighted Signal regulatory protein alpha (SIRPα) is a phagocytic checkpoint in macrophages and other immune cells, as a promising novel therapeutic target in tumor immunotherapy. This review summarizes current progress on SIRPα in HCC and identifies key challenges for future related research.