Since 1984, Danish patients with CSI seminoma have been followed through a uniform 5-year active surveillance program, consisting of regular imaging (CT or MRI), measurement of serum tumor markers (STMs); lactate dehydrogenase (LDH), beta-human chorionic gonadotropin (β-hCG), and alpha-fetoprotein (AFP), and clinical visits with physical examinations [4]. This evidence concerns the gene AFP and seminoma.