Tumors release microvescicles containing protein and RNA fragments, called exosomes, into cerebral spinal fluid, blood, and urine. Exosome Diagnostics, a company based in New York, has developed a diagnostic test able to separate exosomes from bio-fluids and to extract their relevant genomic information. A team of researchers from the Massachusetts General Hospital reported that exosomes preserve the genetic information of their parental cells. By analyzing the genetic material contained in the exosomes, researchers aim to get accurate information about the nature, molecular composition and progression of the tumor.

Providing an early and accurate cancer diagnosis represents one of the major challenges in the battle against tumors. Nowadays a tissue biopsy is generally required in order for the doctors to formulate a correct diagnosis of the type of cancer and its progression status. However, for some tumor types, biopsies are invasive procedures with potential damaging side effects that, in extreme cases, could be life threatening.

A promising alternative to biopsies that hold the potential to revolutionize the cancer diagnosis field comes from studies on the communication between cancer cells and their microenvironment.

A multicenter clinical study using the Exosome diagnostic kit is now underway to validate this new strategy in glioblastoma (the most common form of brain cancer). Clinicians will periodically draw bio-fluids to monitor the state of the disease and will determine whether a patient is responding to therapy, something unthinkable until recently due to the extremely invasive nature of these kinds of biopsies.

Exosome diagnostic kits could potentially detect and monitor the progression of a wide variety of cancers, like prostate cancer. The most common noninvasive test for prostate cancer measures the blood level of PSA, a protein that is produced by the prostate gland. The higher a man’s PSA level, the more likely it is that he has prostate cancer. Nevertheless PSA test alone is not sufficient to accurately and undoubtedly detect prostate cancer. Exosome diagnostic kits specific for prostate cancer represent a substantial alternative to PSA test or they could be used in conjunction with current methods of diagnosis.Although more tests are required, exosomes hold promise to become an invaluable diagnostic tool to be exploited.

http://www.scientificamerican.com/article.cfm?id=rna-fragments-may-yield-rapid