Staining with both neural and mesenchymal markers revealed that NB spheres contained progenitor cells that were able to differentiate into neural cells (positive for GFAP, S100b, DDC or Tuj1), but also into typical mesenchymal-like derivatives, with a remarkable expression of SMA, a marker widely used to label cancer associated fibroblasts [4, 9]. This evidence concerns the gene S100B and cancer.