How Closely Do Circulating Tumor Cells, Cell-Free DNA, and Bone Marrow Biopsies Agree?
Posted: Wednesday, May 23, 2018
Blood biopsies measuring both circulating tumor cells and cell-free DNA agree well with bone marrow biopsy results in patients with multiple myeloma, raising hopes that these less invasive methods could replace bone marrow biopsies for measuring disease progression. These findings were published in Nature Communications by co-senior authors Irene Ghobrial, MD, of Dana-Farber Cancer Institute, and Viktor A. Adalsteinsson, PhD, of the Blood Biopsy Team at the Broad Institute of MIT and Harvard.
“This means that routine genetic profiling of patient tumors from blood would be feasible,” said Dr. Ghobrial in a Dana-Farber press release. “Until now, we haven’t had a good way to measure how multiple myeloma cell populations evolve from precursor stages to diagnosed disease, and then respond to treatments.”
Dr. Ghobrial and colleagues sequenced cell-free DNA from 107 patients and circulating tumor cells from 56 patients. In nine patients, they compared cell-free DNA and bone marrow biopsies, and in four patients they compared all three forms of biopsy. They first performed a round of much less thorough sequencing to inexpensively identify 24 blood samples with enough tumor DNA to proceed and then did whole-exome sequencing on those samples.
The investigators found that both blood biopsies correlated with progression of multiple myeloma. Blood biopsies and bone marrow biopsies agreed 99% in identifying tumor gene mutations and agreed 81% in identifying extra or missing copies of genes. A larger prospective study is an important next step before blood biopsies can clinically replace bone marrow biopsies in multiple myeloma.