Using blood platelets to detect cancer

A recent study in Cancer Cell shows that blood tests based on RNA from tumor-damaged platelets can detect 18 types of cancer. The authors of the study1 note that platelets are considered an alternative source for the detection of cancer and that their role has been known for more than a century.2,3 Along with their function in blood clotting, platelets are involved in inflammation, cancer progression and metastasis.4-6 They are present in large numbers in the bloodstream and can be easily isolated. Researchers tested an algorithm, thromboSeq, capable of detecting early or advanced cancers with a specificity of 99%, as well as the site of origin of the tumor. Read: 400,000 fewer mammograms performed during pandemic: Ontario Medical Association Methodology To train the algorithm for cancer detection, platelet samples were collected from more than 2,400 individuals, of all ages (between 18 and 92) and both sexes, from European and North American populations, representing 18 different tumor types. Also included in the learning process were asymptomatic controls (n = 390), men and women of all ages with no history or signs of cancer or other serious illnesses, and symptomatic controls (n = 333) with specific illnesses ( cardiovascular disease, benign mass or inflammatory condition) without a diagnosis of cancer. Platelet samples were isolated by differential centrifugation within 48 hours of blood draw. Some results Of a total of 1096 blood samples from stage I-IV cancer patients, thromboSeq correctly detected the presence of cancer in two-thirds of cases with a specificity of 99%. For the 352 stage I-III tumors, the algorithm detected half of them. Symptomatic controls gave higher false positive results, with an average specificity of 78%. Prostate cancer was the type of cancer detected most often (11 cases out of 12 with an accuracy of 99%), whereas breast cancer was only detected in around 40% of cases. Finally, the analysis of tumor type-specific RNA profiles validated that platelet RNA can be used to identify the site of origin of the primary tumor. Read: QUIZ: Test your knowledge of recovery after prostate surgery In conclusion, continued optimization of testing, facilitated by machine learning techniques, should allow for more accurate identification of cancer patients as the deposition of platelet RNA samples increases. Further clinical trials will need to be conducted to rule out potential biases associated with various confounding factors. That said, platelet RNA can already complement other molecular sources for the early detection of cancer. References 1. Sjors, G.J.G. et al. (2022). Detection and localization of early- and late-stage cancers using platelet RNA. Cancer Cell 40(9), 999-1009. 2. Sabrkhany S et al. (2019). Platelets: the holy grail in cancer blood biomarker research? Angiogenesis 22, 1-2. 3. In 't Veld S.G.J.G. and Wurdinger T. (2019). Tumor-educated platelets. Blood 133, 2359-2364. 4. Haemmerle M. et al. (2018). The platelet lifeline to cancer: challenges and opportunities. Cancer Cell 33, 965-983. 5. Jiang X et al. (2017). Microfluidic isolation of platelet-covered circulating tumor cells. Lab on a Chip 17, 3498-3503. 6. McAllister S.S. and Weinberg R.A. (2014). The tumour-induced systemic environment as a critical regulator of cancer progression and metastasis. Nat. Cell Biol. 16, 717-727. This article has been translated from its original French and originally appeared on our sister site Profession Santé. Read: A connection between breast cancer and diabetes

Using blood platelets to detect cancer

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