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April 11, 2019

The 'Dark Matter' of Cancer Genomics: Revealing Undetected Structural Variants in Leukemia

Genome Webinar

This webinar reviews a recent study that applied whole-genome sequencing and optical genome mapping to identify a large number of previously undetected somatic structural variants in leukemia samples. 

Genomic analysis has driven major advances in leukemia, where the spectrum of driver mutations provides a much more rigorous classification of disease subtypes, with a correspondingly more robust prognostic power, than previous histological characterization.

In this webinar, Dr. James Broach, Director of the Penn State Institute for Personalized Medicine, discusses a study that indicates there are far more structural variants in leukemia than previously thought.

Dr. Broach and his team combined whole-genome sequencing and optical genome mapping to a number of adult and pediatric leukemia samples. The method identified 97 percent of the structural variants previously reported by karyotype analysis of these samples, as well as an additional fivefold more such somatic rearrangements. 

The method identified on average tens of previously unrecognizable inversions and duplications and hundreds of previously unrecognizable insertions and deletions. These structural variants affected a number of leukemia-associated genes as well as cancer driver genes not previously associated with leukemia and genes not previously associated with cancer. Analysis indicates that the status of several of the recurrently mutated genes identified in this study significantly affect survival of AML patients.

Dr. Broach discusses the implications of the findings, which suggest that current genomic analysis methods fail to identify a majority of structural variants in leukemia samples — an omission that may hamper diagnostic and prognostic efforts.