Since doxorubicin is included in most of the chemoterapeutic regimens for treatment of breast cancers, our results might also suggest that, at least in some cases, the reported relation between high cyclin E levels and poor prognosis in breast cancer patients might simply reflect the reduced responsivity of cyclin E-overexpressing tumours to doxorubicin (Keyomarsi et al, 1994; Nielsen et al, 1996). Here, CCNE1 is linked to breast cancer.