Efficacy and Resistant Mechanism of Eribulin and Bevacizumab for Advanced HER2 Negative Breast Cancer

Inclusion Criteria: 1. Age ≥18 years old，and ≤75 years old. 2. Eastern Cooperative Oncology Group (ECOG) performance status of 0-1. 3. Expected survival period not less than 12 weeks. 4. At least 1 measurable lesion according to RECIST 1.1 standard. 5. previously treated with taxanes and/or anthracycline drugs in any stage of breast cancer. 6. Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) validated HER2 negative, including IHC- and IHC 1+/2+ with FISH negative. 7. at least prior 1 line of chemotherapy in the advanced stage. 8. The organ function must meet the following requirements： (1). Blood Routine * ANC≥1.5×109/L； * PLT≥90×109/L； * Hb≥90 g/L； (2). Blood Biochemistry * TBIL≤1.5×ULN； * ALT and AST≤2×ULN；ALT和AST≤5×ULN for patients with liver metastasis； * BUN and Cr≤1.5×ULN and the Creatinine Clearance Rate ≥50 mL/min (Cockcroft-Gault formula calculated)； (3). Echocardiogram * LVEF≥50%； (4). electrocardiogram * The QT interval (QTcF) corrected by Fridericia method less than 450 ms for male and less than 470 ms for female. 9\. Volunteer to join this study, sign informed consent, have good compliance and be willing to cooperate with follow-up. Exclusion Criteria: 1. There is a third interstitial fluid accumulation that cannot be controlled by drainage or other methods (such as a large amount of hydrothorax and ascites). 2. Symptomatic or uncontrolled brain or meningeal metastases. 3. Patients with only bone or skin metastasis as the assessable lesion. 4. Previously suffered from other malignant tumors. 5. Those who have used Eribulin during the advanced disease stage. 6. Individuals with a known history of allergies to the components of the interventions; History of immunodeficiency, including HIV positive, other acquired or congenital immunodeficiency diseases and a history of organ transplantation. 7. Any heart disease or other conditions evaluated unsuitable by the researcher. 8. Pregnant and lactating female patients, female patients with fertility and positive baseline pregnancy test results, or female patients of reproductive age who are unwilling to take effective contraceptive measures throughout the trial period. 9. According to the investigator's judgment, there are concomitant diseases that seriously endanger the patient's safety or affect the patient's completion of the study (including severe bleeding tendency, history of surgery within 2 weeks, hypertension beyond drug control, serious diabetes, active infection, thyroid disease, etc.). 10. Having a clear history of neurological or mental disorders, including epilepsy or dementia. 11. According to the RECIST 1.1 criteria, researchers determined that patients who received the last anti-tumor regimen before enrollment did not experience disease progression.