Chromosomes, especially homologous chromosomes exchange genetic materials through translocation of their parts in a process called crossing over. If the exchange between the chromosomes is balanced and preserves the proper complement of genetic material, then the chances of the probability of mutation are low. However, if this translocation is uneven and disrupts the regulation of genes (such as activate an oncogene or inhibit a tumor suppressor gene probably due to multiple fusions at a single locus) then the chances of cancer are high.