The spatial chromatin organization in the nucleus has been recognized to be essential for fundamental cell processes. Disruption of its hierarchical structure can be caused by chromosomal rearrangements, which, especially in cancer cells, lead to aberrant molecular signaling, affecting tumor phenotype. We aim to study altered genome structure in chronic lymphocytic leukemia (CLL), the most common type of leukemia of adults in the Western world. We are particularly interested in the complex karyotype (CK) that is known to be associated with poor clinical outcome. We assume that CK plays a key role in chromatin structure disruption, consequently affecting CLL behavior.