The largest analysis so far of DNA copy-number differences in human cancers suggests that several tumour types share significant genetic features. The find, reported in two papers in this week’s Nature, boosts our understanding of cancer biology.

Human cancer cell DNA commonly includes regions that have been copied one or more times, or deleted. Matthew Meyerson and colleagues show that most of the significant somatic copy-number alterations (SCNAs) within any single cancer type tend to be found in other cancer types as well. Alongside other strands of evidence, this suggests that the apparent diversity seen in cancer genomes may reflect combinations of a limited number of functionally relevant events.

Their work analyses more than 3,000 cancer specimens, belonging largely to 26 histological types. The team highlight 158 SCNAs, most of which do not include known cancer target genes. But they do demonstrate a cancer-causing role for the cell suicide genes MCL1 and BCL2L1 that reside in amplifications found in many cancers.

In a related paper, Michael Stratton and colleagues analyse a large number of homozygous gene deletions in a large collection of cancer cell lines. Combined with information about hemizygous deletions of the same genes, these data suggest that many homozygous deletions found in cancer reflect the position of these genes at fragile sites of the genome, rather than recessive cancer genes the loss of which confers a selective growth advantage.


Source: Nature