IGF2 mRNA-binding protein 1 (IMP1) localization is associated with motility, and the major functions of IMP1 are carried out by the phylogenetically conserved K homology (KH) domains. IMP1 can affect stability, localization, and translation of its target RNAs. Binding of IMP1 to the leader 3 mRNA in the 5′-untranslated region (UTR) of IGF2 inhibits translation from a leader 3 reporter mRNA. Aberrant IMP1 expression may interfere with c-myc regulation. In tumors, gains at 8q24 (c-myc locus) were observed to be more frequent than those at 17q21 (IMP1 locus). Furthermore, IMP1 expression was frequently detected in tumors, implying that the mechanism of activation is other than that of gene amplification.