Mayo Clinic researchers have developed a blood-based method that may help detect germ cell tumors, the most common type of testicular cancer, even in cases that are not detected by standard blood tests, according to a study published in December 2016. nature communications.
Testicular cancer most commonly affects adolescents and young adults and is highly treatable, especially if detected early. However, diagnosis can be difficult if the tumor does not produce enough normal blood-based substances, called tumor markers, to be detected by standard tests.
To solve this, researchers used a method that analyzes thousands of immune system signals in the blood at once. Using this approach, they developed a new test called GCT-iSIGN. In a study of 427 blood samples, the test identified 93% of people with germ cell tumors and correctly ruled out cancer in 99% of those who did not. The test also detected 23 of the 24 cases missed by standard blood tests. This gives doctors another way to find these cancers, especially in younger patients.
Researchers have also developed a second test, called Sem-iSIGN, designed to differentiate between the two main types of testicular cancer. This distinction is important because each type may require a different treatment approach.
This finding builds on previous work in which the same research team used immune profiling to identify biomarkers associated with paraneoplastic neurological syndromes associated with testicular cancer, including KLHL11 IgG, previously described in The New England Journal of Medicine.
If standard blood markers are negative, diagnosis and treatment planning may be delayed. Our findings point toward a promising path toward more sensitive blood testing approaches, but additional research is needed before they can be routinely used in patient care. ”
Divyanshu Dubey, MBBS, senior author and corresponding author of the study, professor of laboratory medicine and pathology and professor of neurology at Mayo Clinic
Co-first authors are M. Bakri Hammami, MD, and Andrew M. Knight, PhD. Funding included support from the Department of Defense as well as agency and federal sources.
Mayo Clinic has a financial interest in the technology mentioned in this news release. Proceeds received are used to support Mayo Clinic’s nonprofit mission in patient care, education, and research.
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Reference magazines:
Hamami, M.B. others. (2026). Whole proteome phage immunoprecipitation sequencing reveals a unique immune signature of germ cell tumors. nature communications. DOI: 10.1038/s41467-026-71174-9. https://www.nature.com/articles/s41467-026-71174-9

