Testicular germ cell cancer

It originates in the sperm-producing cells and usually presents as a painless mass, sometimes associated with dull, sustained pain. It is the most common cancer in men, although it is rare, accounting for 2% of all male tumors. Most have a good prognosis, even in advanced stages with dissemination, although it will depend on the type and extension.

The exact cause or causes of testicular cancer are unknown, but a number of factors have been identified that increase the risk.

Cryptorchidism, or undescended testicles before birth, after their formation in the abdominal area during fetal development, carries an increased risk of testicular cancer. Even if the testicle has been surgically relocated to the scrotum, the risk remains elevated. Additionally, conditions that cause the testicles to develop abnormally, such as Klinefelter's syndrome among others, can also increase the risk.

Similarly, HIV infection or its clinical form of acquired immunodeficiency syndrome (AIDS) also slightly increases the risk of developing testicular germ cell tumor seminoma. Other infections by human papillomavirus (HPV), Epstein-Barr virus (EBV), cytomegalovirus (CMV) or Parvovirus B-19 have also been associated with an increased risk of this cancer.

Other risk factors are exposure to certain chemical compounds or tobacco use.

Finally, race also influences risk, with white men being more likely to develop this type of cancer than African-American and Asian-American men.

The development of testicular germ cell cancer is strongly influenced by genetic factors that contribute to a risk of developing the disease close to 50%. In order to obtain a more complete picture of its etiology, a study consisting of a GWAS together with meta-analysis of existing ones, and a replicative study of relevant SNPs including in total more than 7000 cases and 23000 controls, has recently been carried out. This has allowed the confirmation of the significant contribution of up to 39 loci, in a susceptibility model based on transcriptional deregulation, that would contribute to primordial germ cell developmental arrest and chromosomal instability.


Testicular cancer is frequently diagnosed between the ages of 18-45 years, but can occur at any age. Usually the first signs consist of an enlarged testicle or a small lump or area of hardness, while other symptoms usually appear when there is spread to others. Broadly speaking the symptoms of testicular cancer may include:

  • Lump or enlargement in either testicle.
  • A change in the shape of the testicle or a feeling of heaviness in the scrotum.
  • Pain, discomfort, or numbness in a testicle or the scrotum, with or without swelling.
  • Dull pain in the lower abdomen or groin.
  • Sudden accumulation of fluid in the scrotum.
  • Breast tenderness or enlargement.


There is no one way to prevent testicular cancer. As in the prevention of all diseases, it is necessary to maintain a healthy and active lifestyle, stop smoking, follow a diet rich in fruits, vegetables and whole grains, and perform routine physical exercise. It has also been suggested the possibility of performing regular self-examinations of the testicles, however, the most advisable thing to do is to go periodically to the medical check-ups established for each age.

Number of observed variants

13.5 million variants

Number of risk loci analyzed in the study

39 loci


American Society of Clinical Oncology [March 2022]

Gaddam SJ et al. Testicle Cancer [Updated 2021]

Mayo Clinic [March 2022]

Litchfield K et al . Identification of 19 new risk loci and potential regulatory mechanisms influencing susceptibility to testicular germ cell tumor. Nat Genet. 2017 Jul;49(7):1133-1140.

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