Interaction between HER-2 and hormone receptors in breast cancer

Introduction: Breast cancer is the most common malignancy with more than one million new cases diagnosed annually all around the world. Its growth is mostly regulated by steroid hormones such as estrogen and peptide growth factors in interaction with epidermal growth factor 1 and 2. Methods and materials: In this study, 237 patients who had consulted the Oncology Clinic of Tabriz University of Medical Sciences with pathologic diagnosis of breast cancer (from 2003 to 2010) were involved. Data was extracted from medical record. Results: From the total of 237 patients, 50.6% were ER+, 48.9% were PR+ and 37.1% were HER-2+. The greatest percentage of HER-2 positivity (51.6%) was detected in the age group of patients over 60 and the least in the group aged 31 to 40 yrs. The greatest percentage of HR+ (71%) patients were also over 60 and the least (50%) were less than 30. 35.5% of patients in pre- menstrual period were HER-2+. HR was positive in 64% of LN+ patients; HER- 2 and HR were positive in 35.4% and 65.4% while in LN- patients they were positive in 39% and 61.9% of cases, respectively. Conclusion: Acquired data showed reverse relation between the expression of epidermal growth factor II and hormone receptors in breast cancer. 40-55% of cases with epidermal growth factor expression lacked hormone receptors. Co-existence of hormone receptors and HER-2 expression in breast cancer are considered as important prognostic factors.