brain tumor
Credit: Alfred Pasieka/Science Photo LIB / Getty Images/Science Photo Libra

Membrane proteins in urine can indicate a brain tumor early, according to researchers at Nagoya University in Japan. The device could avoid the need for invasive tests and increase the likelihood of tumors being detected early enough for surgery. This research could also possibly be used to detect other types of cancer.

“Urine tests are an effective, simple, and non-invasive method because the urine contains many informative biomolecules that can be traced back to identify the disease,” said Takao Yasui of Nagoya University Graduate School of Engineering.

The study was published in ACS Nano, and the research was led by Yasui and Professor Yoshinobu Baba of Nagoya University’s Graduate School of Engineering.

Although early detection of many types of cancer has contributed to the recent increases in cancer survival rates, the survival rate for brain tumors has remained almost unchanged for over 20 years. Almost 85,000 people a year get brain tumors in the U.S. alone.

Only 36% of brain cancer patients survive more than five years, according to the American Cancer Society.  All of which has led to increased interest in biomarkers for this type of cancer.

Partly, the poor survival rate for brain cancer is due to late detection. Physicians often discover brain tumors only after the onset of neurological symptoms, such as loss of movement or speech, by which time the tumor has reached a considerable size.

Detecting the tumor when it is still small, and starting treatment as soon as possible, should help save lives. And urine testing has many advantages.

One possible sign that a person has a brain tumor is the presence of tumor-related extracellular vesicles (EVs) in their urine. EVs are nano-sized vesicles involved in a variety of functions, including cell-to-cell communication. Because those found in brain cancer patients have specific types of RNA and membrane proteins, they could be used to detect the presence of cancer and its progression.

Although they are excreted far from the brain, many EVs from cancer cells exist stably and are excreted in the urine without breaking down.

This team has developed a new analysis platform for brain tumor EVs using nanowires at the bottom of a well plate. Using this device, they identified two specific types of EV membrane proteins, known as CD31/CD63, from urine samples of brain tumor patients. Looking for these tell-tale proteins could help doctors identify tumor patients before they develop symptoms.

“Currently, EV isolation and detection methods require more than two instruments and an assay to isolate and then detect EVs,” said Yasui.

He added that, “The all-in-one nanowire assay can isolate and detect EVs using one simple procedure. In the future, users can run samples through our assay and change the detection part, by selectively modifying it to detect specific membrane proteins or miRNAs inside EVs to detect other types of cancer. Using this platform, we expect to advance the analysis of the expression levels of specific membrane proteins in patients’ urinary EVs, which will enable the early detection of different types of cancer.”

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