A Pharmacogenomics Study for Breast Cancer Patients Undergoing Adjuvant Chemotherapy With Doxorubicin (A)/Cyclophosphamide ©) and/or Weekly Paclitaxel

Eligibility Criteria

* Histologically confirmed invasive breast cancer
* node negative stage \> T1c or T1b with poor prognostic features (high grade, Her2/neu FISH positive, ER negative) or stage 2 (T2, N0) or
* enrolled on CALGB 40101, CALGB 49909, or the National Cancer Institute of Canada study MA-21 or
* any node positive patient or locally advanced undergoing neoadjuvant chemotherapy with either AC or paclitaxel
* Age greater than or equal to 18 years.
* \>/=2 weeks from major surgery (wide excision / lumpectomy / mastectomy)
* No evidence of systemic metastasis
* Undergoing adjuvant treatment with standard dose AC or AC followed by weekly Paclitaxel at 80mg/m2
* Adequate bone marrow, hepatic and renal functions (absolute neutrophil count \>1,500/ μl, platelet count \> 100,000/ μl, serum creatinine \<2.0 mg/dl, total Bilirubin \<2.0 x the upper limit of normal (ULN)
* Ability to answer and understand study surveillance questionnaires
* No concurrent drug therapy (within 2 weeks) with agents that are known inducers or inhibitors of Cytochrome P450 (CYP450).

Exclusion Criteria

* Other anticancer cytotoxic or endocrine therapy, immunotherapy, or biologic response modifiers,Study Drugs or other concomitant medications known to cause myelosuppression especially neutropenia and neuropathy
* Eastern Cooperative Oncology Group Performance Status(ECOG) functional status \> 2.
* Serious co-morbidities including poorly controlled diabetes mellitus, ischaemic heart disease,uncontrolled hypertension or active infection.
* Pregnancy
* Use of growth factor during cycle 1 of chemotherapy (AC) under pharmacokinetic evaluation
* Grade \>/=2 peripheral neuropathy symptoms based on National Cancer Institute- Common Terminology Criteria for Adverse Events (NCI-CTCAE) Scale. Exception: a chronic neurologic disorder will be reviewed on a case by case basis by the study PI.
* Prior treatment with weekly paclitaxelDISEASE CHARACTERISTICS:

  * Histologically confirmed invasive breast cancer, meeting 1 of the following criteria:

    * Node negative disease AND meets 1 of the following stage criteria:

      * Primary tumor \> T1c
      * Primary tumor \> T1b AND poor prognostic features, defined as the following:

        * High-grade disease
        * Human Epidermal Growth Factor Receptor 2 (HER2)/neu-positive disease by fluorescence in situ hybridization
        * Estrogen receptor-negative disease
      * Stage II disease (T2, N0)
    * Node positive nonmetastatic disease
    * Locally advanced disease AND receiving neoadjuvant chemotherapy comprising doxorubicin and cyclophosphamide OR paclitaxel
    * Enrolled in clinical trial CALGB-40101
  * No evidence of systemic metastasis
  * Hormone receptor status:

    * Not specified