Inclusion Criteria:

1. Patients must have histologically-confirmed breast cancer with an interval between definitive surgery that includes axillary lymph node involvement assessment and initiation of study treatment of less than or equal to 84 days. If the definitive surgery and the axillary lymph node dissection are performed on two different days, both days should be within the 84 day window.

2. Definitive surgery - either mastectomy with axillary node involvement assessment, or breast conserving surgery with axillary node assessment.

   Margins of resected specimen must be free of invasive disease and/or ductal carcinoma in situ (DCIS). The finding of lobular carcinoma in-situ will not be scored as a positive margin.

3. Stage I, II, IIIA, and IIIC (T1-3, N3a only). Patients must be either lymph node positive or high-risk node negative. Node positivity is defined as having invasive adenocarcinoma in at least one axillary node (pN1) or intramammary nodes. At least 6 axillary or intramammary nodes must have been histologically examined. Malignant involvement must be detectable by routine pathologic examination with hematoxylin and eosin staining. Patients with immunohistologic staining as the only evidence of nodal involvement are considered node-negative. High-risk node negative disease is defined as invasive adenocarcinoma not involved in a lymph node determined by Sentinel Node Biospy AND at least one of the following: Tumor size > 2 cm; Estrogen receptor negative; Progesterone receptor negative; Histological and/or nuclear grade 2-3; or Age <35 years.
4. Age > 18 years.
5. ECOG performance status 0 or 1.
6. Normal cardiac function must be confirmed by left ventricular ejection fraction (LVEF) by Echocardiography or MUGA scan and electrocardiogram (ECG) within 35 days prior to initiation of study treatment. The LVEF must be equal to or above the lower limit of institutional normal.
7. Patients must have adequate bone marrow function with ANC > 1500, platelets > 100,000 and hemoglobin >10.0 gm/dl.
8. Patients must have normal liver function (bilirubin within institutional normal limits (wnl) and transaminases < 2.5 times the upper limits of normal. If the transaminases are normal, alkaline phosphatase may be up to 5 x upper limit of normal.
9. Serum creatinine <= 2mg/dl (If greater than 1.5, the creatinine clearance, calculated according to the Cockroft-Gault formula, must be <= 60ml/min).
10. Patients must be able to understand the nature of this study and give written informed consent.
11. Complete staging work-up within 5 weeks prior to initiation of study treatment with the exception of baseline mammography, which must be done within 120 days prior to initiation of study treatment. All patients must have mammography and/or ultrasound, CT scans of the chest, abdomen/pelvis and either a PET scan or Bone Scan.
12. INR < 1.5 or a PT/PTT within normal limits. Patients receiving anti-coagulation treatment with an agent such as warfarin or heparin may be allowed to participate. For patients on warfarin, the INR should be measured prior to initiation of sorafenib and monitored.

Exclusion Criteria:

1. Prior systemic anticancer therapy for breast cancer (immunotherapy, chemotherapy, hormonal therapy).
2. Patients with HER2 positive breast cancer as determined by FISH or IHC3+ standing are ineligible for this trial.
3. Prior anthracycline or taxane therapy.
4. Prior radiation therapy for breast cancer.
5. Bilateral invasive disease.
6. Any T4 or known M1 breast cancer.
7. Pre-existing motor or sensory neurotoxicity of a severity ≥ 2 by NCI CTCAE v 3.0 criteria.
8. Cardiac disease that includes: myocardial infarction; angina, congestive heart failure, arrhythmia; valvular heart disease; cardiomegaly on chest imaging or ventricular hypertrophy on ECG - unless the LVEF is within normal range for the institution; patients with poorly controlled hypertension (defined as systolic blood pressure > 150 and /or diastolic blood pressure > 100 mmHg on antihypertensive medications); patients who receive medications for angina, arrhythmias, or congestive heart failure.
9. Current therapy with raloxifene, tamoxifen or other selective estrogen receptor modulator, either for prevention or osteoporosis.
10. Concurrent treatment with ovarian hormonal replacement therapy.
11. Male patients.
12. History of prior malignancy within 5 years with the exception of skin cancer or cervical carcinoma in situ.
13. Women who are pregnant (positive pregnancy test) or breast feeding. Subjects of childbearing potential must use effective birth control measures during treatment.
14. Treatment with a non-approved or investigational drug within 30 days before day 1 of trial treatment.
15. Patients with active infection requiring parenteral antibiotics.
16. Inability to comply with study and/or follow-up procedures.
17. Patients with neurological symptoms must undergo a CT scan/MRI of the brain to exclude brain metastasis.
18. Known human immunodeficiency virus infection or chronic Hepatitis B or C.
19. Thrombotic or embolic events such as a stroke and transient ischemic attack within the past 6 months.
20. Pulmonary hemorrhage/bleeding event ≥ NCI CTCAE v3.0 Grade 2 within 4 weeks of first dose of study drug.
21. Any other hemorrhage/bleeding event ≥ NCI CTCAE v3.0 Grade 3 within 4 weeks of first dose of study drug.
22. Serious non-healing wound, ulcer, or bone fracture.
23. Major surgery, open biopsy or significant traumatic injury within 4 weeks of first dose of study drug.
24. Use of St. John's Wort or rifampin (rifampicin).
25. Known or suspected allergy/hypersensitivity to any agent given in the course of this trial.
26. Any condition that impairs patient's ability to swallow whole pills.
27. Any malabsorption problem.