Perspective Chapter: Cutting-Edge Genomic Technologies in the Field of Cancer Cytogenetics

Optical genome mapping (OGM), with its high resolution and comprehensive analysis of structural and copy number abnormalities, is revolutionizing the field of cancer cytogenomics. Traditional conventional cytogenetics or karyotyping and fluorescent in situ hybridization are the standard-of-care (SOC) assays in cytogenetic laboratory testing for patient care. Chromosomal microarray analysis (CMA), which offers higher resolution than SOC methods, has been widely adopted in many clinical genetics laboratories. It has the caveat of being unable to detect balanced structural rearrangements, and OGM is still developing for detecting copy-neutral loss-of-heterozygosity, which is part of the recurrent genetic abnormalities in many cancer types, including both hematologic malignancies and solid tumor cancer types. The World Health Organization (WHO), National Comprehensive Cancer Network (NCCN), International Consensus Classification (ICC), and many other international organizations have revised, year after year, the guidelines for detecting genomic alterations in several cancers, which help in diagnosis, risk stratification, and treatment management for patients. The number of such genetic abnormalities continues to grow. Therefore, it is imperative to identify such clinically relevant genomic alterations at the gene level, which is possible with CMA and OGM technologies. This chapter will provide a general overview of how cutting-edge technologies complement traditional cytogenetic methods, along with a few case examples to show the need for incorporating high-resolution whole-genome cytogenomic testing in day-to-day clinical cancer testing.