SPARC and neuroblastoma: To elucidate the effect of SPARC overexpression using a genetic approach and to observe its effects on neuroblastoma tumor growth in vitro and in vivo, we subcloned a human SPARC cDNA in a pcDNA3.1 mammalian expression vector and transfected it into SK-N-AS, NB-1691 and IMR-32 neuroblastoma cells.