MCF10A non-transformed breast cells along with the breast cancer cell lines MDA-MB-231 and Cal51 were infected with retroviruses expressing GFP-tagged Aurora B. Expression of GFP-Aurora B in each of these breast cell lines caused a decreased mitotic index in response to microtubule depolymerization with colcemid, consistent with a weakened mitotic checkpoint (Supplementary Figure S5B). This evidence concerns the gene AURKB and breast cancer.