Abstract

Telomeres are nucleoprotein structures that compose the ends of eukaryotic chromosomes and that regulate chromosome integrity and cell proliferative lifespan. Stabilization of telomere length correlates with cell immortalization, and constitutive activation of telomerase is observed in most human cancers, suggesting that telomere maintenance plays an important role in malignant transformation and possibly aging. However, several lines of evidence indicate that alterations in telomere biology both suppress and facilitate malignant transformation. Moreover, recent observations indicate that telomerase expression plays important regulatory functions beyond the maintenance of telomere length in both normal and malignant cells. Understanding these additional functions of telomerase promise to provide further insight into both normal and malignant cell physiology.