Cultures of these cells established in NB medium supplemented with B27 and bFGF revealed to contain only tumor cells as determined by DNA fluorescent in-situ hybridization using probes detecting the FOXO1 translocation (50 out of 50 cells positive for two copies of rearranged FOXO1) (Fig. 5b, c). This evidence concerns the gene FOXO1 and neoplasm.