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Blood samples reveal competing cell lineages before leukaemia

In the United Kingdom, stored blood samples allowed researchers to reconstruct how competing cell lineages expanded before acute myeloid leukaemia. A peer-reviewed observational study followed 249 samples from 47 women who later developed the disease. Repeated measurements and evolutionary models distinguish slow early growth from faster later expansion, with some lineages dominating blood long before diagnosis.

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Frontal symmetrical view of a glass DNA sequencing flow cell on a benchtop sequencer stage beside a 96-well plate of clear DNA solution and an eight-channel micropipette in a UK genomics laboratory.

Stored samples reveal years of changing blood

Blood collected before illness has allowed researchers in the United Kingdom to follow cell lineages competing years before acute myeloid leukaemia. This aggressive blood cancer can be preceded by expanding populations of cells carrying mutations. The peer-reviewed observational study combined repeated measurements with evolutionary models, identifying lineages that had already become dominant well before a diagnosis. Researchers at the University of Cambridge and University College London reconstructed that process from stored samples.[1], [2]

The material came from the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS), originally established to investigate screening for ovarian cancer. The team analysed 249 prediagnostic samples from 47 women who subsequently developed leukaemia, with 46 participants included in the control comparison. For some women, the earliest available blood sample preceded diagnosis by 15 years. Multiple samples from the same person reveal a trajectory that a single mutation measurement would leave hidden.[1]

Additional mutations change the balance between clones

Error-corrected DNA sequencing helped distinguish rare genetic changes from measurement noise. A clone is a lineage descended from a shared ancestral cell; subsequent driver mutations can give one branch a growth advantage. The mathematical analysis examined both that advantage and competition with other lineages. Many established clones followed trajectories compatible with a relatively simple model of competition, including growth that slowed or reversed as other clones gained ground.[1]

The timescale of an inferred mutation origin is different from the period covered by stored samples. Earlier initiation dates were estimated by fitting the model to later measurements. Its fitness estimates describe an effective competitive advantage under an assumption of a constant effective stem-cell population. That distinction matters when interpreting a reconstructed history extending further back than the blood collection itself.[1]

Some cases show only late expansion

Not every case followed a long, readily visible expansion. Some showed rapid late growth or no clear expansion explained by the genes targeted in the analysis. The researchers also lacked tumour material collected at diagnosis, preventing a definitive link between each earlier lineage and the eventual malignancy. A final transforming event could have occurred after the last sample. The participants were older women, constraining generalization to other populations; the findings describe prediagnostic biology rather than a clinically validated screening test or an established preventive treatment.[1]

References

  1. News sourceNatureSerial blood samples trace clonal competition years before leukaemia↩1↩2↩3↩4↩5
  2. News sourceUniversity of CambridgeSerial blood samples trace clonal competition years before leukaemia↩
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