Optical Genome Mapping Detects Rare and Novel Genetic Drivers in Pediatric B-ALL

Dr. Gordana Raca, Director of the Clinical Cytogenomics Laboratory, Children’s Hospital Los Angeles presented on a pilot study on pediatric Acute Lymphocytic Leukemia (B-ALL) comparing the performance of OGM against standard testing. She presented the actionable finding of a druggable gene fusion that was missed by standard methods and not identified by their custom gene panel, since it was not expected in BALL, illustrating the importance of genome-wide, unbiased structural variation (SV) detection as provided by Saphyr. In half of the studied samples Saphyr identified complex rearrangements entirely missed by standard cytogenetics because karyotyping requires cells to be cultured. Karyotyping therefore can show a skewed picture of the genome since cancer cells often don’t grow well in culture and only the cells that do are analyzed. Saphyr doesn’t require culturing, and thus shows the true state of the cancer genome. Dr. Raca concluded that Saphyr showed important results for research applications and for the clinic, that it was able to detect a large number of variants that were missed by karyotyping and that it can identify the mechanisms that generate cancer driving mutations.