Guided Treatment Based on Mini-PDX in Metastatic Triple Negative Breast Cancer

Inclusion Criteria: * 1\) Women aged 18-70 years; * 2\) an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1; * 3\) Estimated lifetime is ≥ 3 months; * 4\) Histopathologically confirmed recurrent (unresectable) or metastatic triple-negative breast cancer; ER and PR negative is defined as ER \<1% positive, PR \<1% positive. HER-2 negative is defined as HER-2 (-) or (1+) by immunohistochemistry, HER-2 (2+) must be tested by FISH with negative result, HER-2 (1+) (1+), FISH is optional and negative; * 5\) Have at least one measurable target lesion according to RECIST 1.1 criteria; * 6\) Biopsy of the tumor lesion and the specimen passes laboratory quality control; * 7\) A minimum of 2 prior cytotoxic chemotherapy regimens (including at least one line of platinum-containing regimen) in metastatic settings are required prior to enrollment in this trial; * 8\) Adequate organ function, i.e. meeting the following criteria. 1. Hb ≥ 90 g/L (no transfusion within 14 days); ANC ≥ 1.5 × 109 /L; PLT ≥ 75 × 109 /L. 2. Liver function: total bilirubin TBIL ≤ 1.5×ULN (upper limit of normal); ALT and AST ≤ 3×ULN. 3. serum Cr ≤ 1.5×ULN. * 9\) Subjects voluntarily joined the study, signed the informed consent form, were compliant and cooperated with the follow-up. Exclusion Criteria: * 1）Pregnancy or lactation； * 2）History of autoimmune disease； * 3）Anticancer- and radiation therapy-related toxicities have not resolved or downgraded to Grade 1 or less; * 4\) Symptomatic central nervous system (CNS) disease; * 5\) Previous treatment of Immune checkpoint inhibitors; * 6\) History of other malignancies within the past five years, with the exception of cured non-malignant melanoma of the skin and carcinoma in situ of the cervix.