IMP3 and cancer: For these studies, we selected IMP2, which is a member of a family of three conserved oncofetal Ags that is known to be very highly expressed between the zygote and embryo stages (52) IMP2 is also known to be expressed by some cancers (53–55), and there are hypotheses that the IMPs, especially IMP3, have an oncogenic role, although this role appears to have stemmed from association with aggressive and advanced cancers rather than any mechanistic insight (56, 57).