Abstract: Abstract: Objective To observe the expressions of endoplasmic reticulum chaperone (ERP57) and endoplasmic reticulum aminopep- tidase (ERAP1) in female breast cancer, and to explore their relationship with clinical pathological parameters of breast cancer. Methods A total of 124 samples of breast cancer and 24 samples of breast fibroadenoma were collected in the Affiliated Tumor Hospital of Xinjiang Medical University from January 2011 to December 2015. The expressions of ERP57 and ERAP1 were detected by immunohistochemistry SP method. The patients were divided into two groups according to the clinicopathological parameters. The differences of ERP57 and ERAP1 expression were analyzed between the groups. Results The positive expression rates of ERP57 were 58.8% (73/124) and 100% (24/24) in breast cancer and breast fibroadenoma samples, respectively. The difference was statistically significant (χ2=15.061, P＜0.05). The positive expression rates of ERAP1 were 47.5% (59/124) and 83.3% (20/24), and there was a difference between them (χ2= 10.328, P＜0.05). The positive expression rates of ERP57 and ERAP1 in breast cancer samples were higher in patients without axillary lymph node metastasis than those in patients with axillary lymph node metastasis; which were higher in patients with histological grade Ⅰ compared with those in patients with histological grade Ⅱ and Ⅲ; which were higher in patients with TNM stage Ⅰ-Ⅱ than those in patients with TNM stage Ⅲ-Ⅳ. There were significant differences between these groups (P＜0.05). In addition, the positive expression rate of ERAP1 in breast cancer was higher in patients more than 35 years old than those in patients under 35 years old. The positive rate of Ki67 was higher in patients ≤14% than that in patients >14%, and which was significantly higher in patient with non-triple negative than that in patients with the triple negative (P＜0.05). Conclusion The low expression levels of ERP57 and ERAP1 may play an important role in the carcinogenesis of breast cancer, and which may be valuable in judging the malignant degree and prognosis of breast cancer.

Key words: breast neoplasms, endoplasmic reticulum chaperone, endoplasmic reticulum aminopeptidase