As the ALDH1A3 isoform is associated with poor survival in NB and is the most widely expressed ALDH1 isoform in our panel of NB cell lines and PDX tumors (Figs. 5a and 3a, respectively), we asked whether ALDH1A3 activity plays a functional role in NB aggressive phenotype. This evidence concerns the gene ALDH1A3 and neuroblastoma.