Scientists have discovered an autoimmune disease that seems to affect men with testicular cancer. Known as 'testicular cancer-associated paraneoplastic encephalitis' it causes severe neurological symptoms in men. They progressively lose control of their limbs eye movements and in some cases speech. The disease begins with a testicular tumour which appears to cause the immune system attacks the brain. Affected men often find themselves misdiagnosed or undiagnosed and appropriate treatment is delayed. The study published in the 'New England Journal of Medicine' identified a highly specific and unique biomarker for the disease by using a variation of programmable phage display technology.