In addition to its ability to promote recruitment to the gut via its expression on mucosal vessels, VAP-1 has also been implicated in the recruitment of lymphocytes to several human tumours including head and neck cancer and hepatocellular carcinoma where VAP-1 expressed on tumour endothelium was shown to support lymphocyte binding [7, 8]. The gene discussed is AOC3; the disease is hepatocellular carcinoma.