The significance of embryonic reexpression in cancer.

Irradiated syngeneic mouse testicular cells and the first-trimester human fetal tissue cells protect mice partially against tumors induced by methylcholanthrene or against a syngeneic transplantable mouse tumor, Meth A, respectively. For future research it is suggested that experiments should have a therapeutic rather than a prophylactic design and that the induction of tolerance to fetal antigens could be a highly informative procedure.