A New Diagnostic Tool With the Potential to Predict Tumor Metastasis

Extract

A recent discovery that microscopic particles once considered cellular trash are actually oncogenic exosomes may hold the key to diagnosing an individual’s type of cancer and determining its likelihood of future metastasis. A study published in the journal Nature Medicine in May 2012 was the first to show that measuring a melanoma patient’s exosome activity can predict survival.

The findings grew out of earlier work by senior author David C. Lyden, M.D., Ph.D., of Weill Cornell Medical College and Memorial Sloan–Kettering Cancer in New York. “Using confocal and electron microscopy, I noticed flecks that pathologists said were debris were actually homogeneous small particles at future sites of metastasis known as premetastatic niches where the metastatic process is initiated,” said Lyden.

With metastatic melanoma exosomes the focus of the new research, the team examined exosomes in patients with metastatic disease. Because exosomes are found in all biofluids, they used stage IV melanoma plasma samples as a reference for exosome profiling. “We can perform a blood test to determine the exosome number and protein content [and] then correlate that to the stage of disease progression. This has helped validate the use of tumor exosomes as prognostic biomarkers,” explained Lyden.