A paper published last week in Cancer Cell describes a new method for cancer detection from a simple blood sample. So far, one limitation of this type of non-invasive “liquid biopsy” for early detection of cancer has been the inability to identify the nature of the primary tumor. This new method, based on sequencing mRNA from platelets, overcomes this limitation in spectacular fashion—providing accurate identification of the primary tumor location in 71% of the samples tested.
Human blood platelets contain small amounts of mRNA. The RNA profile of “tumor-educated” platelets changes in response to tumor growth as the platelets take up mRNA from tumor cells. In this study, the authors sequenced the platelet mRNA of various cancer patients and healthy donors, and then searched for cancer-associated expression profiles.
The method was used to successfully distinguish samples from cancer patients from those of healthy individuals with 96% accuracy. In addition to pinpointing tumor location, various biomarkers, such as HER2 or KRAS mutations, specific to particular tumor types could also be accurately identified in the sequenced RNA.
It seems that everywhere we turn the power of big data is in the news. This paper is yet another example of the practical application of sequencing-based methods to gain vast amounts of information from a small amount of sample, then compare that information to known databanks to gain highly specific genetic profiles. This particular research gives hope, not only for better non-invasive diagnostic tests, but also for earlier diagnosis and earlier, tumor-specific treatment options.
Here’s the paper:
Best, M.G., et al. (2015) RNA-Seq of Tumor-Educated Platelets Enables Blood-Based Pan-Cancer, Multiclass, and Molecular Pathway Cancer Diagnostics. Cancer Cell 28, 1–11.