Coexpression of both EphB4 and ephrinB2 at high levels in malignancies including melanoma, neuroblastoma and cancers of the prostate, breast, lungs, oesophagus, gastrium, colorectum and uterine endometrium dysregulates cell adhesion and cell motility in tumours (Kyokawa et al, 1994; Vogt et al, 1998; Easty et al, 1999; Walker-Daniels et al, 1999; Tang et al, 2000; Miyazaki et al, 2003). This evidence concerns the gene EFNB2 and cancer.