To determine whether up-regulation of CRLF1 is required for protection of differentiated neuroblastoma cells from 6-OHDA, we employed a loss-of-function strategy in SH-SY5Y cells by identifying lentiviral short hairpin RNAs (shRNAs) that effectively decrease expression of the mRNA transcript by greater than 90% (Fig. S3A). This evidence concerns the gene CRLF1 and neuroblastoma.