IGF2 is a regulatory peptide (IGF-II) critical for normal fetal growth. It has been shown to be implicated in tumor progression in a variety of human neoplasms, eg, Wilms' tumors and rhabdomyosarcomas.

IGF2 transcription is controlled by four distinct promoters, P1 to P4, of which promoters P2, P3, and P4 are epigenetically regulated by genomic imprinting. The IGF-II protein can bind to different receptors: the IGF-I receptor (IGF-IR) has classically been regarded as the major mediator of its proliferative effect; the insulin receptor (IR), especially its isoform A (IR-A), which resembles the IGF-IR in its effect; and the IGF-II receptor (IGF-IIR), which internalizes IGF-II into the cell, thereby regulating its extracellular concentration, and eventually leading to its lysosomal degradation.