In human neuroblastoma cell lines LAN-1, SK-N-SH, and BE(2) (198), GRP stimulation increases the expression of cyclin D and phospho-RB and decreases the expression of the cyclin-dependent kinase inhibitors p21 and p27 (198), which are consistent with GRP’s stimulated increases in the G1/S phase seen on flow cytometric studies and increases in DNA synthesis. This evidence concerns the gene GRP and neuroblastoma.