Serotonin receptors are expressed in the liver and human hepatocellular cancer (HCC). The cover shows the immunohistochemical staining of the serotonin receptor 1B (HTR1B) in a specimen of human HCC. In a subset of tumors, the expression of HTR1B was significantly increased compared with corresponding nontumor liver tissue of the same patient. The expression of the receptor correlated with a higher proliferation rate and tumor size, suggesting an involvement of serotonin receptors in tumor growth of human HCC. For details, see the article by Soll and colleagues on page 5902 of this issue.