Cyclin E expression in breast cancer correlates with negative steroid receptor status, HER2 expression, tumor grade and proliferation.

The main objective of this retrospective study was to investigate relations between cyclin E and pathoclinical factors in patients with operable breast cancer. Expression of cyclin E was analyzed by immunohistochemistry in specimens of invasive ductal breast cancer tissue obtained from 189 women during radical mastectomy. Overall, 110 tumor samples were regarded to be cyclin E positive. Cyclin E expression was more often seen in tumors with: negative steroid receptor status (p<0.0001), higher proliferative index (p=0.0014), higher tumor grade (p=0.0017), and presence of HER2 (p=0.0171). With a median follow-up of 58 months, expression of cyclin E together with negative steroid receptor status determined poor prognosis with a 5-year cancer-specific survival rate of 58%. It differed significantly from a survival curve of cyclin E negative and steroid receptor positive patients (87%, p=0.0005). No significant difference was observed in comparison with survival of cyclin E positive and steroid receptor positive patients (68%, p=0.221). We demonstrated that cyclin E expression in breast cancer cells was associated with negative steroid receptor status, HER2 presence, higher tumor grade and higher proliferation index. Expression of cyclin E together with lack of steroid receptors determined poor prognosis.