IGF2 and neoplasm: Under normal circumstances, the IGF-II gene only expresses the paternal allele, that is, the maternal imprinted gene, as well as 2 tumor suppressor genes, H19 and p57k1p2, in this chromosomal region, which may be caused by the deletion of imprinted genes and the non-expression of tumor suppressor genes.[14] IGF-II gene transcription and translation products are 180 amino acid residues, namely pre-IGF-II, including 24 amino acid peptide N-terminal, 67 amino acid mature IGF-II, and 89 amino acid C-terminal extension, called E-domain.