Brain tumors are some of the most challenging types of cancers to diagnose. When they’re caught by a doctor, the patient often already has neurological symptoms such as partial limb immobility or slurred speech. Japanese researchers at Nagoya University have recognized this problem and have devised a novel microRNA test that can detect brain tumors from less than a drop of urine.

MicroRNAs — not to be confused with mRNA or messenger RNA, which some COVID vaccines employ — are a class of non-coding RNAs that play important roles in regulating gene expression. These tiny molecules of nucleic acid are secreted by various cells in the body, but can also survive undamaged in biological fluids like blood and urine.

The researchers at Nagoya University identified these microRNAs as a potentially reliable biomarker for detecting brain tumors.

“Urine can be collected easily without putting a burden on the human body,” says Nagoya University Associate Professor Atsushi Natsume.

Indeed, rather than employing biopsies and other invasive techniques, the prospect of tumor diagnosis from blood or urine has become increasingly appealing over the years. Previously, ZME Science reported on urine tests that detect different types of cancers, such as prostate, bladder, or lung cancer.

However, up until now, urine-based tests for diagnosing brain tumors have fallen short due to technological barriers in extracting microRNAs from urine.

Like any good engineers, the Japanese researchers led by Natsume made their own device capable of accurately extracting and reading microRNA from urine samples.

The device consists of 100 million zinc oxide nanowires, which are suitable for medical use. The wires can extract a great variety and quantity of microRNAs from a single milliliter of urine.

In order to validate the urine test, the researchers collected urine from patients who were previously diagnosed with brain tumors and non-cancer individuals that acted as a control. Their microRNAs were compared.

The results showed that the test could distinguish patients with brain tumors from non-patients at a sensitivity of 100% and a specificity of 97%, regardless of the malignancy and size of tumors.

Natsume was ecstatic by the promising results, hoping the test could soon contribute to the early diagnosis of some of the most aggressive types of brain cancers, such as glioblastomas.

“In the future, by a combination of artificial intelligence and telemedicine, people will be able to know the presence of cancer, whereas doctors will be able to know the status of cancer patients just with a small amount of their daily urine,” he said.

The findings appeared in the journal ACS Applied Materials & Interfaces.