Histamine receptors are known to be involved in tumor progression in various cancers.24 A recent study suggested that increased expression of histamine receptor H1 is associated with both recurrence-free survival and overall survival in liver cancer patients.25 High expression of histamine receptor H1 in SNU-368 hepatocellular carcinoma (HCC) cells increased HCC cell cycle progression, growth, and metastasis by suppression of cell apoptosis, whereas inactivation of histamine receptor H1 by terfenadine suppressed HCC tumor growth and metastasis.25 This evidence concerns the gene HRH1 and hepatocellular carcinoma.