Angle Plc. You can get HRD status from CTC's by the looks >>25 Sep 2025 15:07
myriad genetics connection?
can you measure cancer hrd status using ctc's?
ai overview
yes, measuring ****logous recombination deficiency (hrd) status using circulating tumor cells (ctcs) is feasible and an area of ongoing research
. hrd status, which is key for predicting the response to parp inhibitors, can be assessed by analyzing the dna from ctcs. however, significant technical challenges remain due to the rarity and heterogeneity of ctcs in the bloodstream.
how hrd status is measured in ctcs
hrd status is typically measured by detecting mutations in ****logous recombination repair (hrr) pathway genes (like brca1 and brca2) or by quantifying the resulting "genomic scars" using next-generation sequencing (ngs). the analysis process generally involves the following steps:
isolating ctcs: since ctcs are extremely rare (as few as 1–10 cells per 7.5 ml of blood), they must first be separated from billions of normal blood cells. various enrichment technologies are used for this, based on either the physical properties (like size) or the biological markers (like epcam) of the cancer cells.
extracting dna: once the ctcs are isolated, their genetic material is extracted for sequencing.
sequencing and analysis: ngs is used to sequence the dna from the isolated ctcs. the genomic data is then analyzed for:
specific gene mutations: pathogenic mutations in genes like brca1 and brca2, which are the most common drivers of hrd.
genomic scar signatures: signs of genomic instability that result from hrd. these include:
loss of heterozygosity (loh): the loss of one copy of a gene.
telomeric allelic imbalances (tai): chromosomal irregularities at the ends of chromosomes.
large-scale state transitions (lst): widespread chromosomal instability.
reporting hrd status: the analysis is used to generate a composite score, known as a genomic instability score (gis), or a report on the specific gene mutations detected.
advantages of using ctcs
minimally invasive "liquid biopsy": unlike traditional tumor biopsies, which are invasive and sometimes not feasible, a ctc liquid biopsy only requires a standard blood draw.
real-time monitoring: ctc analysis offers a real-time snapshot of the tumor's biology, which is crucial for dynamic diseases like cancer. it allows for monitoring changes in hrd status during treatment and can help detect emerging resistance mechanisms.
capturing tumor heterogeneity: as cancer evolves, its genetic and molecular characteristics can change, and these changes may not be captured in a single, static tissue biopsy. analyzing a population of ctcs from the blood can provide a more comprehensive picture of the tumor's spatial and temporal heterogeneity.
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