The use of blood-based liquid biopsies to detect, diagnose, and monitor cancer may enable earlier diagnosis of cancer, lower costs by tailoring molecular targeted treatments, improve convenience for cancer patients, and ultimately supplements clinical oncological decision-making. Current blood-based biosources under evaluation demonstrate suboptimal sensitivity for cancer diagnostics, in particular in patients with localized disease.
So far, none of the current blood-based biosources, including plasma DNA, exosomes, and circulating tumour cells, have been employed for multiclass cancer diagnostics due to the non-specificity of these biosources to pinpoint the nature of the primary tumour. Now, an international study led by researchers at Umeå University has shown that a new RNA test of blood platelets can be used to detect, classify and pinpoint the location of cancer by analysing a sample equivalent to one drop of blood. The team state that this new method for blood-based RNA tests of blood platelets identifies cancer with 96% accuracy. This according to a study at recently published in the journal Cancer Cell.
Previous studies have shown that tumour-educated platelets (TEPs) may enable blood-based cancer diagnostics. Blood platelets, the second most-abundant cell type in peripheral blood, are circulating anucleated cell fragments that originate from megakaryocytes in bone marrow and are traditionally known for their role in hemostasis and initiation of wound healing. More recently, platelets have emerged as central players in the systemic and local responses to tumour growth. External stimuli, such as activation of platelet surface receptors induce specific splicing of pre-mRNAs in circulating platelets. Platelets may also undergo queue-specific splice events in response to signals released by cancer cells and the tumour microenvironment, such as stromal and immune cells. This combination can provide TEPs with a highly dynamic mRNA repertoire, with potential applicability to cancer diagnostics. The current study characterizes the platelet mRNA profiles of various cancer patients and healthy donors and investigate their potential for TEP-based pan-cancer, multiclass cancer, and companion diagnostics.
The current study used blood samples from 283 individuals, where 228 people had some form of cancer and 55 showed no evidence of cancer. Results show that by comparing the blood samples RNA profiles, the presence of cancer was indentified with an accuracy of 96% among patients. Data findings show that among the 39 patients in the study in which an early detection of cancer had been made, 100% of the cases were identified and classified.
In follow-up tests using the same method, the lab identified the origin of tumours with a so far unsurpassed accuracy of 71% in patients with diagnosed cancer in the lung, breast, pancreas, brain, liver, colon and rectum. Results show that the samples could also be sorted into subdivisions depending on molecular differences in the cancer form, which can be of great use in the choice of treatment method. The group conclude that blood platelets could constitute a complete and easily accessible blood-based source for sampling and hence be used in diagnosing cancer as well as in the choice of treatment method.
The team surmise that being able to detect cancer at an early stage is vital and that they have studied how a whole new blood-based method of biopsy can be used to detect cancer. They go on to add that in the study, nearly all forms of cancer were identified, which proves that blood-based biopsies have an immense potential to improve early detection of cancer. For the future, the researchers state that the new method will render an invasive cell tissue sample unnecessary in diagnosing lung cancer, for instance.
Source: Umeå University