CCNB1 and breast cancer: In another study with 332 T1-2 N-negative breast cancers (Kühling et al, 2003; Rudolph et al, 2003), high cyclin B1 expression associated with high grade, high Ki67, cyclin A and E expression, and ER and progesterone receptor (PR) negativity and predicted relapse-free and overall survival in univariate analysis but was not an independent prognostic factor in multivariate analysis including Ki67 as a covariate (Rudolph et al, 2003).