Correlation and frequency of HER-2/neu Status With Estrogen and Progesterone Receptors in Breast Carcinomas


background: Breast cancer is the most common malignant tumor in Iraqi females accounting for a third of registered female cancers. Prognosis and management are influenced by the classic variables such as histologic type and grade, in addition to tumor size, lymph node status, status of hormone receptors of the tumor and HER-2/neu status. HER-2/ neu, also known as c-erb B-2 (HER-2), a proto-oncogene located on chromosome 17, is amplified and/or the protein (HER-2) overexpressed in 15% to 25% of invasive breast carcinomas and is associated with a worse clinical outcome. The interrelationship of ER(estrogen receptor), PR (progesterone receptor), and HER-2 expression in invasive breast cancer has come to have an important role in the management of breast cancer. It has been shown that patients with breast carcinoma overexpressing HER-2 do not respond to tamoxifen therapy.Objectives: To evaluate HER-2/neu overexpression in breast cancer by immunohistochemical study and to study the correlation between HER-2/neu status and expression of ER and PR receptors and other clinicopathological features in invasive breast carcinoma.Patients and methods: Immunohistochemical analyses were performed successfully for ER, PR, HER-2/neu by streptavidin biotin indirect immunohistochemical methods using monoclonal antibodies for 41 specimens of formalin-fixed, paraffin embedded breast cancer tissue.Results:. There was a significant difference in HER-2/neu overexpression between invasive ductal carcinoma of NOS (Not Otherwise Specified) type from other histopathologic types (lobular, and specified type ductal carcinoma). No significant correlation was observed between HER-2/neu overexpression and higher histological grades of invasive ductal carcinoma. The expression of ER or PR was decreased significantly in HER-2/neu positive tumors in comparison with HER-2 negative tumors .Only 7.3 % of all cases (3/41) were negative for estrogen , progesterone receptors (ER/PR) and HER2/neu oncoprotein (Triple negative breast cancers).The two cases of lobular carcinoma and the three cases of the special-type carcinomas were negative for HER-2/neu. Conclusions: HER-2/neu protein was expressed more in ductal carcinoma ( NOS type ) than in lobular or in carcinoma of special type and frequently detected in higher-grade invasive ductal carcinoma tumors.The expression of ER or PR was decreased significantly in HER-2/neu positive tumors. HER-2/neu positivity was not correlated with other clinico-pathological parameters like age of the patient, menopausal state, primary tumor size and axillary lymph nodes status.