To our knowledge this is the first study, where the expression of cyclins A, B1, D1 and E is collectively analysed in breast cancer to determine the correlation with tumour grade and other traditional prognostic factors as well as with basal-like (ER-, PR- and Her-2/neu-, CK5/6+) and triple negative breast carcinomas (ER-, PR- and Her-2/neu-, CK5/6-). Here, ESR1 is linked to breast cancer.