RATIONALE: DNA analysis of tumor tissue may help doctors predict how patients who receive paclitaxel will respond to treatment.

PURPOSE: This laboratory study is evaluating gene expression in predicting response to paclitaxel in patients with breast cancer.

OBJECTIVES:

• Determine whether loss of function of the FEZ1/LZTS1 gene is a predictor of response in patients with breast cancer treated with paclitaxel.

OUTLINE: This is a single-blind study.

Tumor tissue is analyzed for FEZ1/LZTS1 gene expression by immunohistochemistry using an antibody for the gene. Tumor expression of the gene is characterized by immunohistochemistry and scored by intensity of staining, percent of cell staining, and staining index. Tumor tissue is also analyzed for FEZ1/LZTS1 gene disruption by reverse transcriptase-polymerase chain reaction and direct sequencing.

PROJECTED ACCRUAL: Approximately 120 patients will be accrued for this study.

DISEASE CHARACTERISTICS:

• Diagnosis of breast cancer

• Measurable disease

  • Metastatic disease identified by imaging studies OR a primary disease site that will be treated in a neoadjuvant protocol
  • Lesions ≥ 10 mm by spiral CT scan

• Tumor tissue from the primary or metastatic site available for analysis by immunohistochemistry

• Previously treated OR planning to undergo treatment with paclitaxel* NOTE: *Concurrent enrollment on ECOG-2100 allowed

• Hormone receptor status:

  • Not specified

PATIENT CHARACTERISTICS:

• Not specified

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics