Exosome research

Exosomes are lipid-covered microvesicles shed by solid tumors into bodily fluids, such as blood and urine. Current research is being done attempting to use exosomes as a detection and monitoring method for a variety of cancers.^[15][16] The hope is to be able to detect cancer with a high sensitivity and specificity via detection of specific exosomes in the blood or urine. The same process can be used to more accurately monitor a patients treatment progress as well. Enzyme linked lectin specific assay or ELLSA has been proven to directly detect melanoma derived exosomes from fluid samples.^[17] Previously, exosomes had been measured by total protein content in purified samples and by indirect immunomodulatory effects. ELLSA directly measures exosome particles in complex solutions, and has already been found capable of detecting exosomes from other sources, including ovarian cancer and tuberculosis-infected macrophages.
Exosomes secreted by tumors are also believed to be responsible for triggering programmed cell death (apoptosis) of immune cells; interrupting T-cell signaling required to mount an immune response; inhibiting the production of anti-cancer cytokines, and has implications in the spread of metastasis and allowing for angiogenesis.^[18] Studies are currently being done with Lectin Affinity Plasmapheresis (LAP),^[17] LAP is a blood filtration method which selectively targets the tumor based exosomes and removes them from the bloodstream. It is believed that decreasing the tumor secreted exosomes in a patients bloodstream will slow down progression of the cancer while at the same time increase the patients own immune response.