Thrombocytes, or blood platelets, are small, irregular shaped cell fragments that circulate in our blood, and play a role in haemostasis, especially in the formation of blood cloths. Blood generally contains 200-500 million blood platelets per milliliter, which makes platelets a highly available material for research and clinical use. Moreover, blood platelet isolation is relatively simple and is a standard procedure in blood bank/haematology labs. Since platelets do not contain a nucleus, their RNA transcripts – needed for functional maintenance – are derived from megakaryocytes during platelet origination, all other RNAs are acquired during platelet ciculation. Platelet RNA can be readily isolated and subjected to genetic analysis.
We discovered that blood platelets have the ability to ingest nucleic acids, including tumor RNA, providing a safe haven for circulating disease-specific nucleic acids. We demonstrated that tumor RNA markers can be readily detected in blood platelets of cancer patients, in contrast to healthy donors, following the expression pattern in corresponding tumor tissue tissue biopsies. Bioanalyzer results and genome-wide gene expression arrays and RNA Seq revealed RNA of high quality.