Purpose of review: DNA copy number variations (CNVs) comprise a recently discovered element of genetic variation that affects a greater cumulative fraction of the genome than single-nucleotide polymorphisms (SNPs). This review discusses current understanding of the characteristics of CNVs in the human genome and explores the emerging discoveries of both constitutional and somatic CNVs in an ever-expanding variety of human cancers.
Recent findings: The advent of high-resolution SNP arrays has made it possible to identify CNVs. Characterization of widespread constitutional CNVs offers insight into their role in disease susceptibility, whereas somatic CNVs identify regions of the genome involved in disease phenotype. The role of CNVs in cancer has only emerged in the last 2 years, with constitutional CNVs originally being observed in the Li-Fraumeni cancer susceptibility syndrome, and more recently in neuroblastoma.
Summary: It is not yet known how common or how functionally relevant CNVs will be to the process of carcinogenesis. Nonetheless, the inherent instability and structural variability that characterize cancer cell genomes make this form of genetic variation particularly intriguing to the study of cancer.