> Here we report the preliminary results of PanSeer, a noninvasive blood test based on circulating tumor DNA methylation...
I’m very surprised that parts of the methylome, the per-cell state-machine that controls what genes are transcribed, have sufficient serum concentration to be detected. I suspect that this approach should work for any diseased cell targeted by the immune system as long as the disease results in a small but unique methylation signature.
With most of these (cell free DNA) assays, its not a single site that you are measuring but a statistical aggregate about profiles that have been defined for a certain cell type. If you know the overall profile of prostate cells and the profile of normal blood, you can subtract the expected profile from a patient sample and the analyse the left-over fraction for whether it is just noise or is matching to one or multiple known cell types.
The surprise from this publication is only that they detect such signatures 4 years earlier than other non-invasive testing. (although nobody in the cfDNA field would be surprised about that).
There are newer methods that use antibodies to enrich for methylated dna prior to sequencing [1]. The method increases sensitivity as the majority of plasma cfDNA is unmethylated and hematopoietic in origin.
> Here we report the preliminary results of PanSeer, a noninvasive blood test based on circulating tumor DNA methylation...
I’m very surprised that parts of the methylome, the per-cell state-machine that controls what genes are transcribed, have sufficient serum concentration to be detected. I suspect that this approach should work for any diseased cell targeted by the immune system as long as the disease results in a small but unique methylation signature.
[1] https://www.nature.com/articles/s41467-020-17316-z