ERVFRD-1 and seminoma: On the other hand, in the seminomas, the levels of both non-spliced ERVWE1 RNA and spliced syncytin-1 mRNA were significantly higher than the levels of the non-spliced ERVFRDE1 RNA and spliced syncytin-2 mRNA, respectively (P > 0.0001 in both cases, Additional file 6: Fig. S4A and B).