CCND1 and breast cancer: Most studies delineating the prognostic importance for cyclin D1 overexpression in breast cancer have been performed using invasive tumours and the results are diverging: some studies indicate that cyclin D1 overexpression is associated with a negative clinical outcome (Ohta et al, 1997; Kenny et al, 1999), some show no prognostic significance (Michalides et al, 1996; van Diest et al, 1997), while others report a better prognosis for cyclin D1 high tumours (Gillett et al, 1996; Hwang et al, 2003).