Some cases of chronic lymphocytic leukemia (CLL) have acquired mutations that disrupt a protein important for protecting chromosome ends from undergoing rearrangements, reports a study published online this week in Nature Genetics.
CLL affects between one and five per 100,000 adults worldwide. Carlos Lopez-Otin and colleagues analyzed the protein-coding regions of 127 CLL samples from patients and matched normal tissue, with follow-up studies in 214 additional CLL patients. They identified POT1 gene mutations in 3.5% of cases studied. POT1 encodes a member of the shelterin complex, which has an important role in maintaining telomeres, the protective structures present at the ends of chromosomes. These are the first reported mutations in a component of the shelterin complex in human cancer.