“…Similarly, antigens associated with transformation to the malignant state may be expressed (Laurence and Neville, 1972) and choriocarcinoma is neither more nor less likely than other tumours to have such antigens. It is interesting that similar cellular infiltrates to those seen in choriocarcinoma have also been described in other tumours, for example, in carcinoma of the stomach (Black, Opler and Speer, 1954), carcinoma of the breast (Berg, 1962;Black, Opler and Speer, 1956;Hamlin, 1968), malignant melanoma (Cochran, 1969) and neuroblastoma (Lauder and Aherne, 1972). Thirdly, since choriocarcinoma is a malignant allograft (Dowling, 1957;Hirsch, 1962) it may also exhibit individual-specific or transplantation antigens, inherited from the male parent of the antecedent conception.…”