With regard to NB, our study has elucidated that LMO3 forms a nuclear complex with neuronal-specific basic helix-loop-helix (bHLH) transcription factor HEN2, which inhibits another bHLH protein HES1 and consequently leads to upregulation of Mash1, a proneural bHLH transcription factor that is negatively regulated by HES1 and plays a critical role in the development of sympathetic neurons [191]. Here, HES1 is linked to neuroblastoma.