Expressions of Notch1 and Cyclin D1 in Breast Hyperplasia and Cancer

Expressions of Notch1 and Cyclin D1 were analysed by immunohistochemical method in the specimens of normal mammary tissue, usual hyperplasia, atypical hyperplasia, cancer in situ, and invasive cancer tissue, which were obtained from the patients operated due to some kind of breast disease. We observed an evidently decreased Notch1 and increased cyclin D1 expression respectively from normal tissue to invasive cancer, and a negative correlation was drawn between Notch1 and Cyclin D1. No correlation was found between Notch1 expression and any clinicopathologic parameter, but there was positive correlation between the Cyclin D1 expression and ER. This indicated the inhibiting function of Notch1 and promoting function of Cyclin D1 in proliferating process of mammary ductal tissue. From hyperplasia to cancer, there is a continus and sequential process, which suggest an intimate relationship between mammary hyperplasia and breast cancer. Key words-mammary ductal hyperplasia; invasive mammary cancer; Notch1; Cyclin D1; immunohistochemistry