Abstract

Recently, several growth factors, growth factor receptors and oncogenes have been investigated to find out their relations and potential roles in the development and progression of human cancers. Among them, epidermal growth factor receptors (EGFR) have been found in normal and malignant human breast tissues. The purpose of this study was to find out the relation between the expression of EGFR and clinical stage, tumor size, estrogen and progesterone receptor status. We used an improved immunohistochemical staining method for identification of EGFR in formalin-fixed paraffin-embedded section of 45 human breast cancer tissues, 10 normal breast tissues around the cancer masses, l2 metastatic lymph nodes, and 10 breast benign tumor tis- sues using monoclonal antibodies against EGFR. The results were as follows: 1) Immunoreactivity of EGFR was in 57.8% (28/45) of breast cancer tissues, in 10.0% (1/10) of noncancerous breast tissues, in 16.7% (2/12) of metastatic lymph nodes, and in 20.0% (2/10) of benign tmor tissues. 2) The immunoreactivity of EGFR was related to clinical stage; positivity of stage I was 60.0 % (3/5), stage II was 6L1% (l8/29), and stage III was 45.5% (5/1 1 ), respectively. 3) The positivity of EGFR was related to tumor size; positivity of tumor size 0-2 cm was 60.0 / (3/5), tumor size 2-5 cm 61.3% (19/31), tumor size > 5 cm was 44.4% (4/9), respectively. 4) The intensity of EGFR immunoreactivity was increased in stage I and II. 5) Expression of EGFR had an inverse relation between both estrogen and progesterone re- ceptor expressions. with above results, authors considered the expression of EGFR may play an important role in early stage of human breast cancer development, growth and proliferation. And according to the relationship between estrogen receptor and progesterone receptor status, EGFR may offer an additional factor in prognosis of breast cancer.

• Keywords: Breast cancer, EGFR