DIFFERENTIAL EXPRESSION OF ANNEXIN-I IN HUMAN MAMMARY DUCTAL EPITHELIAL-CELLS IN NORMAL AND BENIGN AND MALIGNANT BREAST TISSUES

Annexins are a family of structurally related, water-soluble proteins that have calcium- and phospholipid-binding domains. Annexin I is thou ght to be involved in cell proliferation and differentiation and has r ecently been shown to be expressed on the surfaces of lymphoma cells w here it acts as an endothelial cell adhesion molecule. To evaluate the expression of annexin I in relation to human breast cancer developmen t and progression we used breast biopsy tissues. Immunohistochemical a nalysis of annexin I in paraffin-embedded ductal epithelial cells of v arious human breast tissues indicated that this annexin was not demons trable in the ductal luminal cells of normal breast tissues (n = 11) a nd benign tumors (n = 10) (except for one ductal adenoma) but was gene rally expressed in various types of breast cancers, including noninvas ive ductal carcinoma in situ (DCIS), invasive and metastatic breast tu mors (n = 33). The results suggest that annexin I expression might cor relate with malignant breast cancer progression but it is most likely involved at an early stage of human breast cancer development.