Urine RNA test identified 95 per cent of localized bladder cancers in a study
An experimental urine test identified 95 per cent of localized bladder cancers in a newly published study. It examines tumor RNA shed into urine, carrying information about active genes as well as tumor presence. The Nature Medicine findings open an experimental diagnostic route, but do not establish that the test can replace cystoscopy or improve treatment choices for patients.
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Urine RNA identified localized bladder cancer
An experimental test of RNA shed into urine identified 95 per cent of localized bladder cancers at 90 per cent specificity in a study of 683 urine samples. Sensitivity measures detection among people with disease; specificity measures correct classification among those without it. Researchers at Stanford Medicine, the US university’s medical research organization, and the VA Palo Alto Health Care System developed the method, called uRARE-seq. The findings were published in Nature Medicine.[1], [2]
The team adapted a sequencing method originally developed for blood plasma. Its gene panel detects RNA messages uncommon in healthy urine but more abundant in urinary and reproductive system tumors. RNA reflects which genes cells actively use, providing information about tumor behavior as well as its presence. Samples contained messages from bladder, kidney and prostate tissue, including tumor-derived messages in cancers of those organs.[1], [2]
The locked model was tested in an independent group
The detection model was developed using 100 noncancer control samples and 151 pretreatment bladder cancer samples. Researchers then applied it without changes to a separate validation group of 142 pretreatment cancer samples and 140 controls, finding very similar performance. Among 93 paired samples, RNA profiling detected 89 cancer cases, compared with 32 detected by urine cytology, the standard microscopic examination for cancerous cells.[2]
The study used a case-control design at two affiliated, geographically nearby institutions. Some analyses had modest sample sizes, and unmeasured technical or clinical influences could not be excluded. Researchers plan larger prospective studies to follow patients over time and assess technical performance and clinical usefulness.[2]
Pretreatment RNA differed with immunotherapy response
RNA testing also detected residual disease after surgery and bladder-administered Bacillus Calmette-Guérin, or BCG, immunotherapy. Patients who later responded completely to BCG had stronger pretreatment signals from genes involved in T-cell activity and immune functions. Nonresponders showed more signals associated with rapid tumor-cell division.[1], [2]
Pretreatment samples from 114 patients supported development of a biomarker for response to BCG versus chemotherapy. Treatment was not randomly assigned in the groups validating this model. The findings have not established that the urine test improves treatment choices for patients.[2], [1]
