The Eph (erythropoietin-producing hepatocellular carcinoma) B receptors (EC 2.7.10.1) constitute one-third of the ephrin RTK (receptor tyrosine kinase) subfamily; they are type I transmembrane proteins, and form the largest grouping within the tyrosine kinase family [1]. The gene discussed is EPHA1; the disease is hepatocellular carcinoma.