In apparent contradiction with the hypothesized tumor suppressor effect of the EphB6 molecule in prostate cancer, Fox et al (19) reported that the invasive and metastasizing prostate cancer cell lines DU145, PC-3 and PC-3ML exhibited upregulation of EphB6 mRNA compared with that of cell lines derived from primary prostate cancer or normal tissue. This evidence concerns the gene EPHB6 and prostate cancer.