[Genetics of testicular germ cell tumors].

Testicular cancer is by far the most common neoplasm among young males between the ages of 20 and 40 years and with an increasing incidence rate worldwide. Congenital malformations of the male genitals, such as cryptorchidism or inguinal hernia are established risk factors. Men with a family history of testicular cancer are also associated with an increased risk of the disease. In the testes more than 90 % of tumors develop from germ cells (progenitor cells) and represent a histologically heterogeneous group. Germ cell tumors in extragonadal localizations are rare. Isochromosome i(12p), the typical marker chromosome in testicular germ cell tumors, occurs as an early event in tumorigenesis. Spermatocytic seminoma is a rare variant of germ cell tumors and according to the current classification is a distinct entity with different morphological, clinical and also cytogenetical features compared with other germ cell tumors.