Since 2006, when Fox and colleagues compared the transcripts of all Eph receptors and ephrin ligands in several prostate cell lines, ranging from cultures obtained by the normal prostate epithelium to cell lines established by prostate tumors of varying degrees of metastasis, the possible key role of Eph–ephrin signaling in the development of prostate cancer was highlighted [31]. This evidence concerns the gene EPHA1 and prostate neoplasm.