In Cluster 1, transcripts are over-expressed in the mouse neuroblastoma cell lines in a tumor-restricted manner: Chgb, Dus31, 2310042G06Rik, Psma6 (proteasome subunit), Csnk2a1 (casein kinase), Mtrr (metabolic activation), and Hspa8 (heat shock protein). This evidence concerns the gene MTRR and neuroblastoma.