What causes testicular cancer?

The exact cause of testicular cancer is unknown. The clinical evidence suggests that congenital (born with), environmental and genetic factors play a role.

Testicular cancer develops from the primitive germ cells of the testes. During development the germ cell may be affected by environmental factors, resulting in disturbed differentiation (cell development). Factors that may interfere with normal germ cell development include cryptorchidism (undescended testicle), genetic predisposition or chemical carcinogenesis.

Statistical analysis indicates that one third of patients with germ cell testicular tumours are genetically predisposed to the condition. The marked variation in incidence among different race groups also points to the possible role of genetic factors. On the molecular genetic level all germ cell tumours (including carcinoma in situ) exhibit increased copies of part or all of the short arm of chromosome 12, suggesting that modification of one or more genes mapped to this chromosome play a crucial role in the development of testicular cancer. It is not clear how and when modification of this gene takes place.

The incidence of testicular cancer has increased fourfold over the last five decades. During the same period an apparent decrease in semen quality and an increase in genital abnormalities, such as hypospadia (a penile malformation) and undescended testicles, have been observed.

The higher incidence of testicular cancer in men with testicular atrophy, undescended testes and infertility, suggests a common environmental factor as the most likely link between these genital abnormalities.