DNMT1 and seminoma: Furthermore, the choriocarcinoma cell lines JEG-3 and JAR are strongly positive for DNMT3B, while the seminoma cell line TCam-2 and seminoma tissues displayed only very low expression levels, suggesting that seminomas posses only weak de novo DNA methylation activity, but are able to maintain DNA methylation patterns during replication by the maintenance DNA methyltransferase DNMT1.