Amazing stuff! Cancer is history (soon)!
"... a team reveals that as platelets cruise the bloodstream, they also absorb bits of DNA released by other body cells, including tumor cells. ... for so-called liquid biopsies that diagnose cancer through simple blood tests instead of more invasive sampling of tumor tissue. ...
The team even found that platelets absorb DNA from patients’ precancerous colon growths, which suggests they could be useful for early detection. ..."
"... study ... demonstrates that platelets also act as scavengers, capturing and storing fragments of DNA that are circulating in the blood, including fetal DNA and mutated DNA from cancer cells. Analysis of platelet DNA via a simple blood test was found to reveal the presence of even “pre-cancerous” changes - indicating this may be a powerful technique for the early detection and prevention of cancer. ..."
From the editor's summary and abstract:
"Editor’s summary
Although platelets are best known for their role in blood clotting, they also contribute to host defense and homeostasis. Murphy et al. found that platelets could acquire DNA from nucleated cells by internalizing extracellular vesicles and taking up DNA not enclosed in a membrane, called cell-free DNA (cfDNA) ... ... Human platelets isolated from pregnant individuals contain fetal DNA, and those from cancer patients contain DNA with tumor-associated mutations. Because there is a relatively low concentration of cfDNA in blood plasma, platelets might be an additional source to help overcome a current limitation in clinical diagnostics. ...
Structured Abstract
INTRODUCTION
Platelets are the smallest and second most abundant cell type in our blood, contributing to a range of physiological processes, including hemostasis, vascular maintenance, and innate immunity. ...
RATIONALE
Given their known ability to sense and internalize exogenous nucleic acids, we hypothesized that platelets may sequester endogenous extracellular DNA during circulation. ... cell-free DNA (cfDNA) in plasma, which is immunostimulatory. ...
RESULTS
By using high resolution imaging and flow cytometry, we confirmed that platelets contain fractional quantities of DNA. To test whether platelets can acquire DNA after their release from megakaryocytes, we performed live cell imaging and coculture experiments, demonstrating transfer of mutant DNA from malignant cells to healthy donor platelets in vitro. We confirmed that cfDNA sequestration by platelets occurs in vivo ...
Uptake and release of DNA could be pharmacologically manipulated. Platelet-encapsulated DNA was protected from external deoxyribonuclease (DNase) degradation, and inhibiting platelet exocytosis increased the abundance of DNA obtained from platelets.
Lastly, we demonstrated that tumor-derived DNA was present in platelets of patients with advanced cancer, where cfDNA was in high abundance; in low–tumor burden disease; and also in those with premalignant colonic polyps. ..."
Platelets shown to store DNA in study that could transform cancer screening (original news release) "Oxford-led study uncovers previously unknown function of platelets as DNA ‘vacuum cleaners’ in the blood, with profound implications for cancer diagnosis and prenatal screening."
Platelets sequester cfDNA during circulation.
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