• To determine the objective response rate in patients with ER/PgR/HER2 negative metastatic breast cancer receiving cisplatin as first-line therapy.
  
• To evaluate the expression of p63/p73 in primary tumors from this patient cohort as a biomarker to predict response to cisplatin
  

• To determine the progression free survival, clinical benefit rate, and overall survival in patients with triple-negative metastatic breast cancer receiving first line cisplatin therapy
  
• To evaluate the safety and toxicity of cisplatin therapy in this patient population.
  
• To conduct correlative studies to learn more about the biology of triple negative breast cancer.
  

This study is a Phase 2 study designed to evaluate cisplatin as first line therapy in metastatic triple negative (ER negative, PR negative, Her2 Negative) breast cancer and to evaluate the expression of p63/p73 as a biomarker to predict response.

• Participants will be given a cisplatin infusion intravenously on the first day of each treatment cycle. Each treatment cycle will last 3 weeks.
• During all treatment cycles participants will have a physical exam (including weight and vital signs) and they will be asked general questions about their health and any medications they may be taking, as well as specific questions about any side effects they may be experiencing while receiving study treatment.
• During every treatment cycle participants will have standard blood tests to check blood counts, liver and kidney function, and a blood marker for you particular type of cancer.
• CT scans will be taken of the participants tumor every 2 to 3 cycles to assess the response of the tumor to cisplatin.
• Participants will be in this study for as long as they tolerate the study treatment and their disease does not get any worse.
• Participants will be required to have a sample of their original tumor sent to Massachusetts General Hospital for correlative studies.

Inclusion Criteria:

• Histologically confirmed invasive breast cancer with stage IV disease, according to AJCC 6th edition, either biopsy proven or with unequivocal evidence of metastatic disease by physical examination or radiological study
• All tumors must be ER-, PGR- and HER2-negative
• 18 years of age or older
• Paraffin tissue block is required from the primary tumor tissue or from diagnostic metastatic biopsy at time of relapse
• Measurable disease by RECIST
• Performance status of 0,1 or 2 by ECOG criteria
• Life expectancy greater than 12 weeks
• Normal organ and bone marrow function documented within 14 days prior to enrollment as defined by the protocol

Exclusion Criteria:

• Prior chemotherapy for the treatment of recurrent or metastatic breast cancer
• Prior treatment with cisplatin, carboplatin, or other platinum chemotherapy agents
• Active brain metastases or unevaluated neurological symptoms suggestive of brain metastases
• Intercurrent illness or other major medical condition or comorbid condition that might affect study participation
• Significant history of uncontrolled cardiac disease such as uncontrolled hypertension, unstable angina, recent myocardial infarction, uncontrolled congestive heart failure, cardiomyopathy either symptomatic or asymptomatic but with decreased ejection fraction <45%
• Renal dysfunction for which cisplatin dose would either require dose modification or would be considered unsafe
• Pregnant or nursing women
• History or malignancy that was not treated with curative intent