Genomic instability switch identified

The observation that age and cancer are inextricably linked is clear from the exponential increase in the cases of cancer at the end of human life. Chromosomal abnormalities are seen in all older individuals, cancerous or not, and this genomic instability is considered one of the hallmark prerequisites of cancer. In addition to the mutations that may cause cancer accumulating over time, the rates at which they occur also increase with age. The explanations for this observation are plentiful and hotly debated, but it has been difficult to adequately test these theories. In the September 26 Science, Michael A. McMurray and Daniel Gottschling from the University of Washington used Saccharomyces cerevisiae to study this hallmark of cancer and discovered an age-related switch to genomic instability (Science, 301:1908-1911, September 26, 2003).

McMurray and Gottschling created yeast strains in which they could monitor the loss of marker genes and...