Abstract: [Abstract] Objective To investigate the expression of X-linked inhibitor of apoptosis associated factor 1 (XAF1) and phosphoenolpyruvate carboxykinase 1 (PCK1) in Luminal type B breast cancer and their relationship with the prognosis of patients.Methods From January 2016 to January 2018, 95 patients with Luminal B breast cancer underwent surgical treatment. Cancer tissues and adjacent tissues > 5 cm from the cancer tissues were collected during the operation.The positive expressions of XAF1 and PCK1 proteins were detected by immunohistochemistry.The relationship between XAF1 and PCK1 protein expression and clinicopathological features of breast cancer was analyzed, and the survival curves of breast cancer patients with different XAF1 and PCK1 protein expression were plotted by KaplanMeier method,the survival rate was compared by Log-rankn test. Multi-factor Cox-regression analysis was used to analyze the prognostic factors of breast cancer.Results GEPIA database analysis showed that the expression levels of XAF1 and PCK1 mRNA in breast cancer tissues were lower than those in normal tissues ( P<0.05).The positive expression rates of XAF1 and PCK1 proteins in cancer tissue were lower than adjacent tissues ( P<0.05).The positive expression of XAF1 in breast cancer tissue was related to clinical stage,lymph node metastasis and histological grade,Ki-67 expression status,while the positive expression of PCK1 was related to clinical stage,lymph node metastasis and Ki-67 expression status ( P<0.05).The 5-year overall survival rate of XAF1 positive expression patients was higher than that of negative expression patients (Log-rank χ²=5.101， P=0.024),and the 5-year overall survival rate of PCK1 positive expression patients was higher than that of negative expression patients (Log-rank ^χ2=6.515, P=0.011).Clinical stage Ⅲ,negative expression of XAF1,and negative expression of PCK1 were risk factors for poor prognosis ( P<0.05).Conclusion The positive expression rates of XAF1 and PCK1 in Luminal B type breast cancer tissue are reduced,which is related to some clinicopathological characteristics and 5-year survival rate after surgery.The 5-year survival rate was lower in patients with negative XAFI and PCKI expression.

Key words: breast cancer, Luminal B type, Xlinked inhibitor of apoptosis associated factor 1, phosphoenolpyruvate carboxykinase 1, prognosis