Bionano Genomics, Inc. announced the publication of a peer-reviewed study that compared optical genome mapping (OGM) to classical cytogenetic techniques used for analysis of solid tumor cancer samples consisting of soft tissue and bone sarcomas, including fluorescence in situ hybridization (FISH) and karyotyping (KT). OGM demonstrated high levels of concordance with FISH and KT but was also shown to exclusively detect alterations in known oncogenes and tumor suppressor genes and to identify additional pathogenic aberrations, including chromothripsis and chromoplexy, that were not detected by multiple other cytogenetic methods. Sarcomas represent over 100 histological subtypes and are highly heterogenous in their genetic landscape and prognosis.

Accurate diagnosis of these tumors is dependent on the identification of underlying genetic aberrations, which can include large, and often complex, structural variants (SVs) or copy number variants (CNVs) involving oncogenes or tumor suppressor genes. The detection of SVs and CNVs remains challenging and typically requires multiple traditional cytogenetic techniques. In this study, researchers demonstrated OGM?s ability to detect aberrations as small as 500 bp, which is approximately 10,000-fold higher resolution than that of KT.

As shown in this study, OGM can provide better characterization of the genomic complexity of sarcoma samples when compared to traditional cytogenetic techniques, due to the workflow?s high resolution and ?comprehensive, genome-wide analysis. Key findings: OGM was concordant with traditional methods for the detection of pathogenic variants in 32 out of 35 cases (91%), OGM detected loss of CDKN2A/B in 9 out of 38 cases (24%), all missed by classical methods, which is associated with poor prognosis? in soft tissue sarcomas.OGM uniquely detected chromothripsis in 9 out of 35 cases (26%).

In 5 out of 25 cases (20%) with diagnostic fusions, OGM showed that chains of rearrangements generated the fusions, three of which involved chromoplexy.