Irene Ghobrial, MD, Dana-Farber Cancer Institute, Boston, MA, comments on the potential of using whole-genome sequencing (WGS) of circulating tumor cells (CTCs) to detect the emergence of high-risk genetic subclones in patients with multiple myeloma. Dr Ghobrial explains that CTCs can be used as a prognostic marker as well as to monitor disease progression and tailor therapy, and argues that this technology could replace standard molecular cytogenetics techniques such as FISH. This interview took place at the 19th International Myeloma Society Meeting (IMS) held in Los Angeles, CA.