CELF1 and neuroblastoma: CELF2 was identified almost 20 years ago, in multiple studies, first as a CUG repeat binding protein CUG-BP2 (Timchenko et al., 1996); in screens for homologs of the Elav family (ETR-3) (Lu et al., 1999); and as a gene induced in apoptotic neuroblastoma cells (NAPOR) (Choi et al., 1998).