Researchers have developed a urine test combined with a medical imaging test that allows for a two-phase diagnosis of cancerous tumors: screening and monitoring the progress of metastasis. This procedure could be used to monitor recurrence after treatment or to perform routine cancer screenings.

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Most of the tests used by physicians to diagnose cancer, such as mammography, colonoscopy and computed tomography (CT), are based on imaging. More recently, researchers have also developed molecular diagnostics that can detect specific molecules associated with cancer that circulate in body fluids such as blood or urine. Engineers at MIT have created a new diagnostic technique that combines these two features: it can reveal the presence of cancer proteins through a urine test and functions as an imaging agent, pinpointing the location of the tumor.

In principle, this diagnostic could be used to detect cancer anywhere in the body, including tumors that have metastasized from their original location. A metastasis is a tumor formed from cancer cells that have broken away from a first tumor and migrated to another part of the body where they have taken up residence. It is not another cancer, but the original cancer that has spread. "This is a very broad sensor designed to respond to both primary tumors and their metastases. It can trigger a urine signal and also allow us to visualize where the tumors are," the researchers explain.

Detecting a cancerous tumor through urine

In their study published in the journal "Nature Materials" they showed that this type of diagnosis could be used to monitor the progression of colon cancer, including the spread of metastatic tumors to the lungs and liver. They hope that eventually it could be used as a routine test that could be performed annually. Their technique is based on the principle of synthetic biomarkers that can be easily detected in urine, because most cancer cells express enzymes called proteases. The nanoparticles developed by the researchers, to be ingested, can "bind" to these proteases, making them cancer "markers".

Concretely, when these particles encounter a tumor in the body, they are excreted in the urine where they can be easily detected by doctors. In animal models of lung cancer, this process has allowed for early detection of tumors. However, the researchers were confronted with the fact that it does not reveal the exact location of the tumor or whether it has spread beyond its organ of origin. So they wanted to develop a "multimodal" diagnostic, which can perform both molecular screening (urine signal detection) and imaging, to tell exactly where the original tumor and metastases are located.

An easy-to-implement routine screening test

To modify the particles so that they could also be used for imaging, the researchers added a radioactive tracer. This new process was tested in two mouse models of metastatic colon cancer, in which tumor cells grow in the liver or lungs. After treatment with a chemotherapy drug commonly used to treat colon cancer, the scientists were able to use both the urine signal and the imaging agent to successfully track the response of the tumors to treatment. this type of diagnosis could therefore prove useful for early detection and for assessing the response of patients to treatment.

Although the study is currently being conducted only in mice, the researchers hope that this type of diagnostic could also be used to monitor patient remission. "These patients could be followed with the urine version of the test every six months. If the test is positive, they could be followed up with the radioactive version for an imaging study that could indicate where the disease has spread. Both modes of testing use one formulation. Every year, you could do a urine test as part of a general health check-up," the scientific team notes. This diagnosis would be particularly useful for patients who cannot access a screening facility, which they consider too costly.