Consistent with previous report (Yoon et al., 2012), we showed that the expression of PTTG1 is significantly higher in malignant Hs578T and MDA-MB-231 breast cancer cell lines than that in less malignant SK-BR3 and MCF-7 breast cancer cells and normal breast epithelia cells, as determined by western blot (Figure 1), indicating the involvement of PTTG1 in breast cancer malignancy. Here, PTTG1 is linked to breast cancer.