Mosaicism, aging and cancerMachiela, Mitchell J.Current Opinion in Oncology: March 2019 - Volume 31 - Issue 2 - p 108–113 doi: 10.1097/CCO.0000000000000500 CANCER BIOLOGY: Edited by Pierre Hainaut Abstract Author InformationAuthors Article MetricsMetrics Purpose of review Genetic mosaicism is the presence of a somatic mutation in a subset of cells that differs from the inherited germline genome. Detectable genetic mosaicism is attractive as a potential early biomarker for cancer risk because of its established relationship with aging, introduction of potentially deleterious mutations, and clonal selection and expansion of mutated cells. The aim of this review is to survey shared risk factors associated with genetic mosaicism, aging and cancer risk. Recent findings Studies have associated aging, cigarette smoking and several genetic susceptibility loci with increased risk of acquiring genetic mosaicism. Genetic mosaicism has also been associated with numerous outcomes including cancer risk and cancer mortality; however, the level of evidence supporting these associations varies considerably. Summary Ample evidence exists for shared risk factors for genetic mosaicism and cancer risk as well as abundant support linking genetic mosaicism in leukocytes to hematologic malignancies. The relationship between genetic mosaicism in circulating leukocytes and solid malignancies remains an active area of research. Integrative Tumor Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, USA Correspondence to Mitchell J. Machiela, Integrative Tumor Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, 9609 Medical Center Drive, Rockville, MD 20892-9774, USA. Tel: +1 240 760 6518; e-mail: firstname.lastname@example.org Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.