Abstract: Expression and Significance of Human Epidermal Growth Factor Receptor 2 in Estrogen andProgesterone Receptor Negative Breast CancerQin ZHANG, Hong LIU, Jing ZHAOCorrespondence to: Hong LIU, E-mail: lh713@163.comSecond Department of Breast Oncology, Tianjin Medical University Cancer Institute and Hospital, Key Laboratory of Breast CancerPrevention and Therapy, Tianjin Medical University, Ministry of Education. Key Laboratory of Cancer Prevention and Therapy, Tianjin300060, ChinaAbstract Objective: To compare the clinicopathologic characteristics and prognosis between triple negative breast cancer andother types of breast cancer that overexpress human epidermal growth factor receptor 2 (HER-2) and to investigate the prognostic fac-tors of estrogen and progesterone receptor (ER, PR) negative breast cancer. Methods: A retrospective study of 1,250 female unilateralbreast cancer patients undergoing surgery in our hospital in 2004 was performed. Patients with triple negative breast cancer and HER-2overexpressing breast cancer were identified using immunohistochemistry and FISH. The clinicopathologic characteristics, recurrenceand survival of the patients were summarized. Results: The median follow-up time was 60 months (range, 6-73 months). No significantdifference was found between the phenotype and age, age at menopause, histological grade, or PCNA expression. Triple negative breastcancer patients had a higher percentage of breast cancer family history ( 8.9 & 4.3, P = 0.010 ) and P53 expression ( 64.4 & 60.7, P =0.006 ). Patients with breast cancer overexpressing HER-2 experienced more lymph node metastasis and were more likely to have me-tastasis in more than 4 lymph nodes (36.6 & 29.7, P = 0.004 ). They also had a higher percentage of stage Ⅲ and Ⅳ disease (18.3&29.3, P = 0.014 ). No significant difference in distant metastasis or 5-year disease-free survival was found between the two subtypes (P > 0.05 ). Conclusion: Patients with triple negative breast cancer exhibit many different clinical and histopathological features consis-tent with their specific biology and pathogenesis, and they have 5-year relapse and survival rates similar to patients with ER- andPR-negative, HER2 overexpressing breast cancer. Thus, it is proposed that HER-2 overexpression is not a prognostic factor for ER- andPR-negative breast cancers.Keywords Breast neoplasm; HER-2; Clinicopathologic features; Prognosis