Our Science
The Goal
For diseases such as cancer, early detection can have a profound impact on the chances of survival. How can we detect a disease before the onset of symptoms? A good solution would be to routinely test ourselves by means of a non-invasive blood (or urine) test to find molecules that can be traced back to the disease.
B4-RNA’s technology leverages the release of RNA into the blood to find these tumors. Although healthy cells also release RNA into the bloodstream, tumors express a unique set of RNA molecules that can be measured, and with the help of an AI-based platform we can identify patterns that signal the existence of these tumors at an early stage.
Why hasn’t this been done before?
The problem is that most RNA molecules released into the blood are cleaved by RNA-degrading enzymes called RNases, that are abundant in the blood and other bodily fluids. This has so far limited the broad application of RNA-based liquid biopsies.
Our discovery
We have discovered a group of RNA molecules that are inherently resistant to degradation. These molecules are cleaved by RNases once released into the blood, but they are so structured that they are not destroyed by these enzymes. In contrast, they remain as discontinuous, damaged RNA molecules.
We call these damaged RNA molecules “nicked RNAs”, because they do contain one or a few “nicks” in their structure.
Current sequencing methods however are not designed for sequencing these discontinuous, nicked RNAs. When attempting to reverse-transcribe these molecules, reverse-transcriptases fall-off from the RNA template. As a result, these inherently stable and abundant molecules circulating in the bloodstream are invisible to standard sequencing methods. When applying denaturing agents for RNA extraction, nicked RNAs are broken into small fragments that can be sequenced, but these fragments are too short to be unambiguously assigned to their parental genes since they look too similar to one another.
Let’s think about this problem as a jigsaw puzzle. If we break nicked RNAs into short fragments, each fragment is like a unique piece in the puzzle. All pieces look similar, so it’s almost impossible to understand what the jigsaw puzzle represents by just looking at individual pieces.
We need a better strategy to sequence these circulating RNAs.
Our innovation
If we open the puzzle box and find that most of the pieces are already joined together, we have a much better chance of understanding the bigger picture.
Our proprietary RNA sequencing method (patent-pending) is based on the repair of nicked RNAs extracted under non-denaturing conditions, in order to generate a repaired molecule that we can now sequence without losing important information. Instead of obtaining many ambiguous short fragments, we obtain longer reads that we can unambiguously assign to specific genes. This enables us to distinguish between genes that are expressed at high levels by cancer cells, and genes that are expressed by other healthy cells in the body.
AI to the rescue
Joining two pieces together is how we start solving our jigsaw puzzle, but this by itself is not enough to understand the hidden meaning – we need to massively repeat this process to reach our ultimate goal. Our method does not rely on studying just one or two repaired RNAs, we study millions simultaneously to achieve a good discriminative power that can distinguish the blood of a patient with early-onset cancer from a healthy individual.
Fortunately, the technology to generate and analyze massive amounts of data is already here, and we are developing a proprietary AI-driven analysis pipeline to do so. Our main differentiating factor is that thanks to our RNA repair method, we have exclusive access to a group of potential disease biomarkers that cannot be sequenced without our technology.
We are currently conducting clinical trials to assess the sensitivity and specificity of our RNA-based liquid biopsy for different applications ranging from cancer screening to treatment monitoring and cancer recurrence detection, with the aim of obtaining regulatory clearance of our unique and state-of-the-art molecular diagnosis platform.
Our publications
- Nature – The biologist on the hunt for extracellular ribosomes (Khamsi, 2020). The first description of extracellular ribosomes and tRNAs, as commented in a news article published in Nature.
- NAR – Fragmentation of extracellular ribosomes and tRNAs shapes the extracellular RNAome (Tosar et al. NAR 2020). A detailed article about extracellular ribosomes and tRNAs, also featured in the cover.
- PNAS – Nicked tRNAs are stable reservoirs of tRNA halves in cells and biofluids (Costa et al. PNAS 2023). The first description of inherently stable nicked RNAs, and how to repair these molecules to be able to sequence them.
- Nature Protocols – Small RNA structural biochemistry in a post-sequencing era (Tosar et al. Nat Protocol 2024). A perspective article on small RNA sequencing techniques, where we introduced REJOIN-seq – B4-RNA’s proprietary sequencing method.