Studying Tissue Samples From Women Who Underwent Chemotherapy for Lymph Node-Positive Stage II or Stage IIIA Breast Cancer on Clinical Trial CLB-9741 or CLB-9344

ER/HER2/Ki67 Breast Cancer Subtypes as Predictive Factors for Response to Adjuvant Dose-dense Therapy, and Basal Subtypes of Double-negative Breast Cancer as Prognostic Factors in Intergroup Trial C9741

RATIONALE: Studying samples of tumor tissue from patients with cancer in the laboratory may help doctors learn more about changes that occur in DNA and identify biomarkers related to cancer. It may also help doctors plan the best treatment.

PURPOSE: This research study is looking at tissue samples from women who underwent chemotherapy for lymph node-positive stage II or stage IIIA breast cancer.

OBJECTIVES:

Primary

• To identify biomarkers that can be used to individually tailor the use of adjuvant dose-dense therapy in women with stage II or IIIA breast cancer.

Secondary

• To identify groups of patients who have a poor prognosis despite adjuvant chemotherapy and who should be prospectively targeted for new approaches to adjuvant treatment.

OUTLINE: This is a multicenter study.

Tissue samples are collected from patients. Tissue samples are analyzed by immunohistochemistry (Ki67, CK5/6, EGFR, ER) and fluorescence in situ hybridization (FISH).

DISEASE CHARACTERISTICS:

• Diagnosis of node-positive breast cancer

  • Stage II-IIIA disease

• Underwent adjuvant chemotherapy on trial CLB-9741 or CLB-9344

• Hormone receptor status not specified