Background and Aims: Tumor invasion and metastasis are the main causes of death in breast cancer. The study of molecular markers of breast cancer is helpful for diagnosis and prognosis estimation. The relationship between apoptotic gene survivin and nuclear transcription factor NF-κB in breast cancer tissue is still unclear. This study was conducted to investigate the expressions of survivin and NF-κB protein in breast invasive ductal carcinoma and their relations with the clinicopathologic features, molecular subtypes and prognosis of the patients, so as to expand the understanding and knowledge of the pathogenesis for breast cancer and provide new strategies for the treatment and prevention of breast cancer.
Methods: Eighty patients with invasive ductal breast cancer who underwent surgical treatment in the People's Hospital of Zhengzhou from May 2015 to May 2017 and had confirmed pathological diagnosis and complete clinical data were selected as study objects. The expressions of survivin and NF-κB protein in the tumor and adjacent tissues from the patients were determined by immunohistochemical staining. The relations of survivin and NF-κB protein expressions with the clinicopathologic variables and molecular subtypes as well as prognosis of the patients were analyzed by statistical methods. 
Results: The positive expression rates of both survivin and NF-κB protein in cancer were significantly higher than those in adjacent tissue (53.75% vs. 11.25%; 56.25% vs. 8.75%, both P<0.05). Both expressions of survivin and NF-κB were associated with histological grade, lymph node status and TNM stage, and both expressions were increased in breast cancer tissue of poor differentiation, positive lymph node metastasis, advanced TNM stages and non-luminal subtypes (all P<0.05); meanwhile, the co-overexpression rates of survivin and NF-κB were higher in breast cancer tissue of poor differentiation, positive lymph node metastasis, advanced TNM stages and non-luminal subtypes (all P<0.05). There was a positive correlation between survivin and NF-κB expressions (r=0.546, P=0.000). Survival analysis showed that the 5-year disease-free survival rate of patients with either high survivin or NF-κB expression was lower than those of the patients with corresponding low expression, and the 5-year disease-free survival rate of patients with co-overexpression of survivin and NF-κB was lower than that of the patients with either high survivin or NF-κB expression alone as well as patients with co-downexpression of survivin and NF-κB (all P<0.05). Cox regression analysis showed that NF-κB, co-expression of survivin and NF-κB, tumor diameter, differentiation and lymph node metastasis were independent risk factors for the prognosis of patients with invasive ductal breast cancer (all P<0.05).
Conclusion: The expressions of survivin and NF-κB protein in invasive ductal breast cancer tissue are closely related to the malignant clinicopathologic features and unfavorable prognosis of the patients, and furthermore, there may be a synergistic action between survivin and NF-κB in promoting the occurrence and development of breast cancer.