A study by Johnsen et al.75has shown that Akt expression could be detected in all NB primary samples, but nonmalignant adrenal medullas lack this Akt expression. In addition, it has been found that catalytic p110α and the regulatory p85α isoforms of PI3K are more highly expressed in NB cell lines and primary NB samples compared with normal adrenal gland tissue.76 This evidence concerns the gene PIK3CA and neuroblastoma.