Danish scientists said on Thursday they had discovered a new method that could help to detect very early signs of Testicular cancer.

They diagnosed the disease in a 23-year-old man, who had fertility problems but no signs of testicular cancer, by looking for a specific protein in semen.

“This is the first time there may be a potential method of detecting testicular cancer in a semen sample,” Dr. Christina Hoei-Hansen, of Rigshospitalet-Copenhagen University Hospital, told AMN Health.

She believes the findings could lead to the development of a cheap, non-invasive diagnostic test and perhaps a screening program for testicular cancer.

The researchers had earlier discovered that a protein called AP-2gamma was found in testicular carcinoma in situ (CIS), a very early stage of the disease before it has started to spread.

They were conducting a study to compare levels of the protein in semen samples from testicular cancer patients with that from healthy men who acted as a control group.

“When we were evaluating the first series of semen samples we detected AP-2gamma positive cells in a sample from one of the healthy controls,” Hoei-Hansen said.

The man was having a routine semen analysis because he and his partner had been trying for 18 months to have a baby. Further tests confirmed he had CIS, according to the research reported in the journal Human Reproduction.

The patient underwent surgery to remove the diseased testicle. He and his partner are now awaiting the birth of their first child, which was conceived naturally, according to the study.