Source 1primary paper2021Molecular Oncology
Toolkit/cell-free chromatin immunoprecipitation
cell-free chromatin immunoprecipitation
Also known as: cfChIP
Taxonomy: Technique Branch / Method. Workflows sit above the mechanism and technique branches rather than replacing them.
Summary
Cell-free chromatin immunoprecipitation (cfChIP) is an assay method that immunoprecipitates histone mark-associated cell-free chromatin from blood plasma. In the cited study, cfChIP targeting H3K36me3-associated cfDNA was used with droplet digital PCR to infer transcriptional activity of specific genes, including EGFR, in the cells that released the cfDNA.
Usefulness & Problems
Why this is useful
cfChIP is useful for extracting transcription-state information from plasma-derived cell-free DNA rather than measuring only sequence variation. The cited work indicates that H3K36me3-associated cfDNA can report whether a particular gene is being transcribed in the source cells and can distinguish enrichment of mutant versus wild-type EGFR fragments in NSCLC plasma.
Problem solved
This method addresses the problem that conventional cfDNA analyses primarily detect genotype but do not directly indicate whether a specific gene is actively transcribed in the cells shedding the DNA. The reported cfChIP approach uses a transcription-associated histone mark, H3K36me3, to infer gene expression status from circulating chromatin fragments.
Problem links
cfChIP provides a way to infer otherwise hidden transcriptional activity from histone mark-associated cell-free chromatin. It is actionable and measurement-oriented, but it addresses a narrow extracellular proxy of gene activity rather than direct, multiplex single-cell measurement of proteins, lipids, or metabolites.
Taxonomy & Function
Primary hierarchy
Technique Branch
Method: A concrete measurement method used to characterize an engineered system.
Mechanisms
allele-specific enrichment detection by ddpcrallele-specific enrichment detection by droplet digital pcrimmunoprecipitation of histone mark-associated cell-free chromatintranscription-state inference from h3k36me3-associated cfdnaTechniques
Functional AssayTarget processes
transcriptionImplementation Constraints
cofactor dependency: cofactor requirement unknownencoding mode: genetically encodedimplementation constraint: context specific validationoperating role: sensor
The reported implementation uses blood plasma as the input material and immunoprecipitation of H3K36me3-associated cell-free chromatin. Detection of allele-specific enrichment was performed by droplet digital PCR comparing EGFR-L858R and EGFR-WT fragments in NSCLC patient samples.
The supplied evidence is limited to a single 2021 study focused on EGFR in non-small-cell lung cancer plasma samples. No broader performance metrics, sensitivity limits, antibody requirements, or validation across additional histone marks, genes, or disease contexts are provided in the evidence.
Validation
Cell-freeBacteriaMammalianMouseHumanTherapeuticIndep. Replication
Supporting Sources
Ranked Claims
cfChIP of H3K36me3-associated cfDNA has the potential to delineate whether transcription of a particular gene is occurring in the cells from which its cfDNA originates.
cfChIP of H3K36me3-associated cfDNA has the potential to delineate whether transcription of a particular gene is occurring in the cells from which its cfDNA originates.
cfChIP of H3K36me3-associated cfDNA has the potential to delineate whether transcription of a particular gene is occurring in the cells from which its cfDNA originates.
cfChIP of H3K36me3-associated cfDNA has the potential to delineate whether transcription of a particular gene is occurring in the cells from which its cfDNA originates.
cfChIP of H3K36me3-associated cfDNA has the potential to delineate whether transcription of a particular gene is occurring in the cells from which its cfDNA originates.
cfChIP of H3K36me3-associated cfDNA has the potential to delineate whether transcription of a particular gene is occurring in the cells from which its cfDNA originates.
cfChIP of H3K36me3-associated cfDNA has the potential to delineate whether transcription of a particular gene is occurring in the cells from which its cfDNA originates.
In blood plasma from NSCLC patients harboring EGFR-L858R, H3K36me3 cfChIP followed by ddPCR revealed significantly higher enrichment of EGFR-L858R fragments than EGFR-WT fragments.
In blood plasma from NSCLC patients harboring EGFR-L858R, H3K36me3 cfChIP followed by ddPCR revealed significantly higher enrichment of EGFR-L858R fragments than EGFR-WT fragments.
In blood plasma from NSCLC patients harboring EGFR-L858R, H3K36me3 cfChIP followed by ddPCR revealed significantly higher enrichment of EGFR-L858R fragments than EGFR-WT fragments.
In blood plasma from NSCLC patients harboring EGFR-L858R, H3K36me3 cfChIP followed by ddPCR revealed significantly higher enrichment of EGFR-L858R fragments than EGFR-WT fragments.
In blood plasma from NSCLC patients harboring EGFR-L858R, H3K36me3 cfChIP followed by ddPCR revealed significantly higher enrichment of EGFR-L858R fragments than EGFR-WT fragments.
In blood plasma from NSCLC patients harboring EGFR-L858R, H3K36me3 cfChIP followed by ddPCR revealed significantly higher enrichment of EGFR-L858R fragments than EGFR-WT fragments.
In blood plasma from NSCLC patients harboring EGFR-L858R, H3K36me3 cfChIP followed by ddPCR revealed significantly higher enrichment of EGFR-L858R fragments than EGFR-WT fragments.
This study provides proof of principle that cfChIP can be used to identify tumor-specific transcriptional activity of mutated alleles.
This study provides proof of principle that cfChIP can be used to identify tumor-specific transcriptional activity of mutated alleles.
This study provides proof of principle that cfChIP can be used to identify tumor-specific transcriptional activity of mutated alleles.
This study provides proof of principle that cfChIP can be used to identify tumor-specific transcriptional activity of mutated alleles.
This study provides proof of principle that cfChIP can be used to identify tumor-specific transcriptional activity of mutated alleles.
This study provides proof of principle that cfChIP can be used to identify tumor-specific transcriptional activity of mutated alleles.
This study provides proof of principle that cfChIP can be used to identify tumor-specific transcriptional activity of mutated alleles.
In representative NSCLC cell lines, both wild-type EGFR and EGFR-L858R are transcribed, and mRNA is similarly expressed per EGFR copy.
In representative NSCLC cell lines, both wild-type EGFR and EGFR-L858R are transcribed, and mRNA is similarly expressed per EGFR copy.
In representative NSCLC cell lines, both wild-type EGFR and EGFR-L858R are transcribed, and mRNA is similarly expressed per EGFR copy.
In representative NSCLC cell lines, both wild-type EGFR and EGFR-L858R are transcribed, and mRNA is similarly expressed per EGFR copy.
In representative NSCLC cell lines, both wild-type EGFR and EGFR-L858R are transcribed, and mRNA is similarly expressed per EGFR copy.
In representative NSCLC cell lines, both wild-type EGFR and EGFR-L858R are transcribed, and mRNA is similarly expressed per EGFR copy.
In representative NSCLC cell lines, both wild-type EGFR and EGFR-L858R are transcribed, and mRNA is similarly expressed per EGFR copy.
Approval Evidence
1 source3 linked approval claimsfirst-pass slug cell-free-chromatin-immunoprecipitation
cell-free chromatin immunoprecipitation (cfChIP)
Source:
assay capabilitysupports
cfChIP of H3K36me3-associated cfDNA has the potential to delineate whether transcription of a particular gene is occurring in the cells from which its cfDNA originates.
Source:
proof of principlesupports
This study provides proof of principle that cfChIP can be used to identify tumor-specific transcriptional activity of mutated alleles.
Source:
transcription observationsupports
In representative NSCLC cell lines, both wild-type EGFR and EGFR-L858R are transcribed, and mRNA is similarly expressed per EGFR copy.
Source:
Comparisons
Source-backed strengths
The cited study reports that H3K36me3 cfChIP has the potential to delineate whether transcription of a particular gene is occurring in the cells from which its cfDNA originates. In blood plasma from NSCLC patients harboring EGFR-L858R, H3K36me3 cfChIP followed by ddPCR showed significantly higher enrichment of EGFR-L858R fragments than EGFR-WT fragments.
Compared with qRT-PCR
cell-free chromatin immunoprecipitation and qRT-PCR address a similar problem space because they share transcription.
Shared frame: same top-level item type; shared target processes: transcription
Relative tradeoffs: appears more independently replicated.
cell-free chromatin immunoprecipitation and real-time reverse transcription polymerase chain reaction address a similar problem space because they share transcription.
Shared frame: same top-level item type; shared target processes: transcription
cell-free chromatin immunoprecipitation and time-resolved imaging of nucleoid spatial distribution after drug perturbation address a similar problem space because they share transcription.
Shared frame: same top-level item type; shared target processes: transcription
Ranked Citations
- 1.