Mitosis is the process by which the nuclear material is divided and transmitted to the next generation of cells in eukaryotic organisms. It is not only an essential process for life, but mitotic abnormalities have also been related with aneuploidy and chromosomal instability observed in many human cancers. Aneuploidy is also the basis of many birth defects and the main cause of spontaneous abortions in humans. Clearly, elucidating the molecular mechanisms behind chromosome segregation fidelity will have broad biological significance, while contributing to unveil the routes of aneuploidy and their implications to human health/disease. The major goal of our laboratory is to understand how chromosome segregation is regulated in time and space and how mitotic failure may lead to aneuploidy, contributing to a better understanding of how cancer arises and how it could be treated.