Can prenatal irradiation protect the embryo from tumor development?

Abstract

Although the processes of cell proliferation and differentiation are--without comparison--most pronounced during early embryonic life, this period, before and during organogenesis, appears to be highly resistant to carcinogenesis. One possible explanation for this paradox could be that cancer is controlled by the regulators influencing development, regulators that are most active during early embryonic life. In addition, it seems that under certain conditions, as shown by experiments on rat brain, prenatal irradiation can decrease rather than increase the subsequent carcinogenic effect of a chemical carcinogen. The possible reasons for this are discussed.