To the Editor.—Bolande1 has drawn attention to the benign nature of neonatal tumors and discussed the concept of cancer repression in early life. There are two other tumors that could be added to his list. The yolk sac tumor of the testes has a much better prognosis in younger patients. More important, in over 700 cases of Burkitt's lymphoma reported from Africa, there were no patients under one year old.
I have already suggested an alternative reason for these findings.2 The improved prognosis could be related to passive immunity inherited from the mother. Passive immunological defenses are maximal at birth and decay slowly thereafter until active immunologic defense mechanisms take over. There is some experimental evidence to support this theory. Mothers and close relatives of children with neuroblastoma are immune to neuroblastoma antigens. Moreover, it has been shown that at least the mothers have cytotoxic antibodies