For example, it was shown that patients who have stage 2 neuroblastoma with MYCN amplification are at higher risk than those without it (Rubie et al, 1997; Alvarado et al, 2000; Perez et al, 2000), but another study demonstrated that the presence of MYCN amplification in localised neuroblastoma does not necessarily indicate an adverse outcome (Cohn et al, 1995). This evidence concerns the gene MYCN and neuroblastoma.