Stanford urine RNA test spotted 95% of localised bladder cancers and may predict who benefits from BCG

Researchers at Stanford Medicine and the VA Palo Alto Health Care System have described a urine test for bladder cancer in Nature Medicine (Liu et al.); Stanford publicised it on 5 October 2026.

The problem

About 85,000 people in the US are diagnosed with bladder cancer each year. It often recurs, and monitoring relies on cystoscopy — a camera passed into the bladder — which can miss up to 30% of cancers and may be needed every three months for high-risk patients. Many patients then get BCG immunotherapy, but it does not work for everyone, and supplies come from a single global manufacturer and are often short.

The test

The test, uRARE-seq, measures cell-free RNA shed into urine rather than DNA mutations. RNA reflects which genes a tumour is actively using, so it shows what the cancer is doing, and it avoids confusion from harmless mutations in normal bladder lining (the “field effect”), without needing a matched tumour sample.

Results

• In 683 urine samples from patients and healthy volunteers, it detected 95% of localised bladder cancers and correctly classified 90% of people without cancer, outperforming standard urine cytology and a DNA-based urine test.
• It detected residual disease after surgery and BCG.
• Patients who later responded to BCG had urine RNA rich in T-cell and immune-signalling genes; non-responders showed signs of fast-dividing tumour cells. From this the team built a biomarker to predict whether immunotherapy or chemotherapy is more likely to work.

Limitations and conflicts of interest

This is not yet a clinical test: the authors plan larger, prospective, multi-centre trials to validate it, and accuracy figures from a development study often fall in independent cohorts. The lead author and several co-authors have ownership interests in Resero Bio, a Stanford spin-out commercialising the technology, and senior authors have filed related patents. Anyone with symptoms such as blood in the urine should talk to their doctor.