Many Eph receptors and ephrin ligands are known to be involved in the development or progression of malignant tumors: Upregulation of EphA2, A7, A10, and ephrinA2 and B3 is thought to be involved in tumorigenesis and/or invasiveness, while downregulation of EphA1, A3, A4, A8, B3, B4, B6, and ephrin A1 and B1 may be particularly important in tumor invasiveness (7). The gene discussed is EPHA1; the disease is cancer.