IOS Press Letter to the Editor

Low rates of aneuploidy promote tumorigenesis while high rates of aneuploidy cause cell death and tumor suppression ∗ Sir, An abnormal chromosome number, a condition known as aneuploidy, is a common characteristic of tu-mor cells. Because of this correlation, Boveri proposed aneuploidy to be a cause of tumorigenesis 100 years ago [1,2]. However, this hypothesis remained untested due to the difficulty of selectively generating aneu-ploidy in the absence of other defects, particularly DNA damage. We determined that cells and mice with reduced levels of the mitosis-specific, centromere-linked motor protein CENP-E develop aneuploidy and chromosomal instability in vitro and in vivo in the absence of other defects, including DNA damage