The formation of abnormal mitosis associated with cancer has been intriguing for many decades. While microtubules had been the focus of previous studies, recent research has focused on centrosomes, microtubule organizing centers which organize the mitotic apparatus during cell division. During normal mitosis centrosomes form two poles but in cancer, centrosomes can form three, four, or more poles, and organize tripolar, quadripolar, and multipolar mitoses, respectively. This has severe consequences for genomic stability because chromosomes are separated unequally to three, four, or more poles. This can result in aneuploidy and gene amplifications with multiple defects in cellular regulation. It can result in malignancy that is accompanied by cell cycle imbalances and abnormal cell proliferation. While radiation and chemical agents are known to damage DNA and can lead to cell cycle abnormalities, the damage of centrosome structure leading to abnormal mitosis deserves also consideration.