Inverse correlations between NM23-H1 expression and high tumor metastatic potential in several tumor types, e.g. hepatocellular carcinoma, melanomas, breast cancer, ovarian cancer and gastric cancer, have been demonstrated [38-41] In other human carcinomas, such as colon cancer, pancreatic ductal carcinoma, neuroblastoma and non-Hodgkin’s lymphoma, high mRNA and protein levels of NM23-H1 have been detected in aggressive tumors [25,42-47]. This evidence concerns the gene NME1 and neuroblastoma.