Evaluation of Cyclin D1 expression by western blotting methods and immunohistochemistry in breast cancer patients

Purpose: Considering that cyclin D1 had a prognostic and clinical value for breast cancer patients, adequate measurement of cyclin D1 is necessary. Methods: In this investigation, we detect cyclin D1 expression in tumour and peritumoral tissue of breast cancer patients by Western blotting method and by immunohistochemistry. Results: Cyclin D1 expression decreased significantly with each advanced clinical stage of disease and tumour size. Also, patients without lymph node involvement, with positive hormone receptors and Luminal A type of tumours had significantly increased the expression of cyclin D1. We show that cyclin D1 expression correlates with longer RFS in the entire group of patients, in the group of ER-positive and in the group of HER2-negative patients. Patients who were both ER and cyclin D1 positive had a better prognosis. Conclusion: Taken together, our results, showing correlation of cyclin D1 with clinical stage, tumour size and lymph nodes, suggest that cyclin D1 expression, detected by Western blotting, could be considered as an additional marker for the staging of breast cancer, as well as a marker for longer RFS and survival in ER-positive breast cancer patients.