TCF7L2 and neuroblastoma: Finally, treatment of N2A cells with RSPO2, a leucine rich repeat-containing G-protein coupled receptor (LGR) ligand that has been shown to amplify Wnt signal in a subset of neuroblastoma cells [30], did not induce significant changes in either Tcf7L2, Paupar or Pax6 (Fig 3F).