Genetically homozygous choriocarcinoma following pregnancy with hydatidiform mole.

Genetic studies have been made in two cases of primary choriocarcinoma from patients in whom the antecedent pregnancy was a hydatidiform mole. Restriction fragment length polymorphisms of the DNA from the tumour, the patient and her partner were examined and in both cases the tumours were shown to be androgenetic in origin, having only paternal polymorphisms. While one tumour was shown to be heterozygous, two different paternal alleles being demonstrated with some probes, the other tumour was shown to be homozygous for all informative polymorphisms examined. Thus choriocarcinoma can follow complete hydatidiform mole which may be either heterozygous or homozygous.