The largest study of the genetics of testicular germ cell tumours has uncovered four new genetic variants associated with increased risk of testicular cancer – the most common cancer in young men.

According to the Institute of Cancer Research (ICR), genetic testing could identify men at a 10-fold increased risk of the disease.

The research, published today in Nature Communications, was led by scientists at the Institute, which is part of the University of London, and funded by the Movember Foundation, Cancer Research UK and the ICR.

It discovered the four new variants through analysing the DNA of 6,059 patients with testicular cancer, and comparing it with the DNA of 19,094 people without the disease. The four new variants add to the 21 already known.

Dr Clare Turnbull, senior researcher at the ICR, said: “Applying these 25 variants, we found that men in the top one percent for testicular cancer risk were at a more than ten-fold elevated risk of developing the disease compared with the average – although that still adds up to only around a five per cent (one in twenty) chance of developing testicular cancer. 

She added: “If we can identify more of the genetic variation underlying testicular cancer, this sort of testing might be used clinically to help identify those at most risk of testicular cancer before they develop the disease, such that we can offer measures to help stop them from developing testicular cancer.”

The sizes of the effects of some of the genetic variants associated with testicular cancer risk are quite high – compared with breast and prostate cancer, for example, where most variants each have only a very small effect, said the ICR. A man in the top one per cent of genetic risk had a five percent lifetime risk of developing testicular cancer, more than 10 times higher than that of the average man.

ICR chief executive, Professor Paul Workman, said: “This important study adds detail to the emerging picture of testicular cancer as a strongly heritable disease [and] provides some evidence that genetic screening in selected groups of men could be a long-term possibility. We also need to look at this new genetic information and see if it can direct the discovery of new, more targeted treatments.”