Telomere length heterogeneity and chromosome instability

Chromosome aberrations are the hallmark of cancer cells. Although a few specific chromosome aberrations are frequently detected in some types of cancer, the majority of karyotypic abnormalities tend to differ between different histological types and between individuals with the same type of cancer. Recent work indicates that telomeres may be directly involved in shaping the karyotypes of tumor cells. In particular, the heterogeneity of telomere lengths within cells may have a direct influence on the frequency with which chromosomes engage in telomeric fusions and in subsequent breakage-fusion-bridge cycles. Since telomere length distribution among chromosome arms is a polymorphic trait, difference in distributions between individuals may account, at least in part, for the karyotypic differences found among tumors of the same type. Conversely, if single telomere lengths happen to be inherited, the segregation of particularly short telomeres in families may increase the incidence of specific chromosome aberrations during tumor evolution, and perhaps contribute, along with other factors, to cancer pre-disposition. (C) 2004 Elsevier Ireland Ltd. All rights reserved.