OBJECTIVE: We conducted this study to analyze the mechanism behind the high coagulation state induced by circulating plasma microparticle tissue factor (MP-TF) in patients with breast cancer. PATIENTS AND METHODS: 87 cases of breast cancer patients (10 cases of TNM stage I, 16 cases of II, 32 cases of III, 29 cases of IV; 8 cases of pathological type in situ carcinoma, 15 cases of ductal carcinoma, 64 cases of invasive cancer) were used as the observation group and 20 cases of benign breast lesions were used as the control group to compare MP-TF levels of plasma and coagulation parameters including prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB) and D-dimer body (D-D) level and NF-kappa B signaling pathway index including P50, p65, TAK1 and I kappa Ba levels. RESULTS: The plasma MP-TF level in the observation group was significantly higher than that in control group, and the level of MP-TF in the observation group increased with an increase in depth of TNM stage and tumor invasion; differences were statistically significant (p<0.05). In the observation group, the plasma PT and APTT were shortened, and the levels of FIB and D-D were increased; the differences were statistically significant (p<0.05). In the observation group, the levels of P50, p65, TAK1, I kappa Bain circulating blood were higher than those in control group; the differences were statistically significant (p<0.05). After the Pearson test, the plasma levels of MP-TF in patients with breast cancer were negatively correlated with PT and APTT, and positively correlated with FIB, D-D values and the levels of p50, p65, TAK1 and I kappa Ba (4 p<0.05). CONCLUSIONS: MP-TF can lead to high blood coagulation in patients with breast cancer through the activation of NF-kappa B signaling pathway, which may become a new target for the intervention of the disease.