New research may help explain the effects of mutations that help maintain telomeres, the protective tips of chromosomes, in certain types of tumors (Heaphy CM et al. Science. doi:10.1126/science.1207313 [published online ahead of print June 30, 2011]).
In many cancers, an increased level of the enzyme telomerase helps keep telomeres intact, which helps cancer cells divide without normal limits. Investigators at the Johns Hopkins Medical Institutions in Baltimore found that inactivating mutations in the genes ATRX and DAXX may destabilize chromosomes' protective tips, but they also initiate a mechanism called alternative lengthening of telomeres (ALT) that allows tumor cells to maintain telomere length independent of telomerase.
Hampton T. Tumors and Telomeres. JAMA. 2011;306(5):480. doi:10.1001/jama.2011.1087