Haim Cohen, Ph.D
Department of Pathology,
Harvard Medical School,
Boston, MA
The incidence of cancer increases as we age: during the last decade of life, the risk of developing cancer is a startling 50% for men and 33% for women.1 What is the underlying link between aging and cancer? This link may be found by investigating diseases that are associated with both a high frequency of cancer and premature signs of aging. Such diseases, known collectively as RecQ syndromes, are caused by mutations in genes encoding RecQ-like proteins.2 The RecQ family of proteins has a high degree of homology to the helicase domain of the RecQ helicase of E. coli. The helicase region is required for all RecQ helicases to unwind duplex DNA from 3' to 5' direction in vitro; however, the in vivo function of the eukaryotic RecQ is unknown.
At least three inherited human diseases are caused by mutations in RecQ-like genes: Werner syndrome (WS), Bloom syndrome (BS), and Rothmund-Thomson syndrome (RTS).3 These diseases share two main features: premature aging and a high level of genomic instability that manifests itself as a high incidence of cancer.
The hallmark of Bloom syndrome is an increased level of sister chromatid exchange, and patients present with sun-sensitive skin pigmentation and a predisposition to certain malignancies.
