In the interphasic nucleus, chromosomes are non-randomly arranged within the nuclear space. Indeed, chromosomes are thought to be organised into "chromosome territories". The size of a chromosome territory is roughly determined by its DNA content, but is also influenced by other factors, such as their transcriptional status. Chromatin modifications and positioning of genetic loci in the nucleus play a critical role in the control of gene expression. Emerging evidence suggests that the nucleus is structurally and functionally compartimentalized and desorganization of such a structure might play a major role in the emergence of human diseases such as cancer.