Genomic instability leads to cancer. Also genomic instability promotes diversity of the malignant cells within the tumour. DNA damage and chromosome nondisjunction are the two major causes of gross instability. We aim to study both problems and their relationship with the life and death of the cell. We use the model organism Saccharomyces cerevisiae as well as actual tumour tissues to gain insights into the complexity of the maintenance of the integrity of the genome. We are also interested in drugs that affect the DNA and their effects on how the can reshape the genome.