Expression of cell-cycle regulatory proteins BUBR1, MAD2, Aurora A, cyclin A and cyclin E in invasive ductal breast carcinomas.

Cyclin A, cyclin E, BUBR1, MAD2 and Aurora A are all cell-cycle regulatory proteins and have been proven to play crucial roles in carcinogenesis. However, their expression patterns in invasive ductal breast carcinoma (IDBC) are controversial and unclear. In this study, we examined the expression status of these candidate proteins in a set of 117 invasive ductal carcinomas, and evaluated their associations with known clinicopathological parameters and the expressions of estrogen receptor, progesterone receptor, Ki-67 and Her-2. Univariate and multivariate data analyses both displayed that positive BUBR1 expression was associated with a high Ki-67 labeling index, and negative MAD2 expression was associated with Her-2 overexpression. Positive BUBR1 expression was also associated with a high histological tumor grade in univariate analysis, but not in multivariate analysis. In addition, high Aurora A expression was weakly associated with lymph node metastasis, and cyclin A was strongly associated with the expression of cyclin E in both univariate and multivariate models. In conclusion, this study suggests that evaluation of BUBR1, MAD2 and Aurora A expression levels is likely to improve accuracy of prognostic predictions in IDBC.