Inclusion Criteria:

* Pathologic confirmation of invasive breast cancer; patients with inflammatory breast cancer are not eligible
* Clinical stage II-III operable invasive breast cancer with intent to perform surgical resection after neoadjuvant therapy

* Patients with multicentric or bilateral disease are eligible as long as the target lesion meets the eligibility criteria for this study
* Staging to rule out metastatic disease is recommended for clinical stage III patients
* Tumors must be HER2 positive defined as HER2 3+ by immunohistochemical (IHC) assays or gene amplification by fluorescence in situ hybridization (FISH) with a ratio of >= 2 on invasive tumor
* Estrogen receptor (ER) and progesterone receptor (PgR) status must be known
* The target lesion in the breast must be >= 1 cm on physical examination or by radiographic measurement; palpable axillary adenopathy will be documented but not serve as measurable disease for the primary endpoint; patients with axillary disease only are not eligible to participate
* Patient agrees to provide pretreatment biopsies
* No prior chemotherapy, hormone therapy, biologic, or radiation therapy with therapeutic intent for this cancer
* Cardiac ejection fraction must be >= 50% by echocardiogram or multiple gated acquisition (MUGA) scan
* Eastern Cooperative Oncology Group (ECOG) (Zubrod) performance status 0-1
* Patients must not be pregnant or nursing
* Absolute neutrophil count (ANC) >= 1,000/ul
* Platelet count >= 100,000/ul
* Bilirubin =< 1.5 times upper limit of normal
* Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) =< 2.5 times upper limit of normal (ULN)
* Serum beta-human chorionic gonadotropin (HCG) negative (in female patients unless status-post (s/p) hysterectomy or menopausal or no menses for 24 consecutive months); assay must have a sensitivity of at least 50 mIU/mL