While provirus c22_A is found expressed in all seminoma samples, and in orchitic and atrophic testis samples, with an average relative cloning frequency of approx. 22% (range 4.5%–60% for gag cDNAs; 0%–70% for env cDNAs), no cDNA corresponding to provirus c22_A was found in the three normal testis samples, despite very similar numbers of analyzed cDNAs (Fig. 3). This evidence concerns the gene ERVW-1 and seminoma.