When soluble ENO1 Ag is released into the tumor microenvironment or circulation, it can interact with anti-ENO1 Ab and form an immune complex, which is promptly cleared by macrophages in the liver or spleen [31, 32], resulting in a lower level of circulating anti-ENO1 Ab in cancer patients with tumor cells overexpressing ENO1. This evidence concerns the gene ENO1 and neoplasm.