Circulating tumor DNA as a liquid biopsy in plasma cell dyscrasias

Multiple myeloma (MM) is a clinically and genetically heterogeneous malignant proliferation of plasma cells (PCs) with a typical multifocal distribution in the bone marrow (BM) and occasional extra-medullary dissemination. Advances in the genetic knowledge of MM are increasingly translated into biomarkers to refine diagnosis, prognostication and treatment of patients. MM genotyping has so far relied on the analysis of purified PCs from the bone marrow (BM) aspirate, which may fail in capturing the postulated spatial heterogeneity of the disease and imposes technical hurdles limiting its transfer in the routine and clinical grade diagnostic laboratory. In addition, longitudinal monitoring of disease molecular markers may be limited by patient discomfort caused by repeated BM samplings during disease course.