NCAM1 and neuroblastoma: The role of polySia-NCAM as a key regulator of tumour cell migration was demonstrated in neuroblastoma cells in vitro [37] and both siRNA knock-down of ST8SiaII and enzymatic removal of polySia by endoneuraminidase (EndoN, which specifically removes polySia from NCAM) both independently lead to abolition of cell migration in tumour cells [38].