RATIONALE: Studying the genes expressed in samples of tumor tissue from patients with cancer may help doctors identify biomarkers related to cancer.

PURPOSE: This research study is looking at tumor tissue samples from patients who have undergone surgery for breast cancer.

OBJECTIVES:

• To determine if candidate genes display differential expression between normal and cancer breast tissues.

OUTLINE: Previously collected breast cancer tissue samples (paraffin embedded blocks) and normal adjacent tissue are used for immunohistochemistry studies of expression of candidate genes.

Inclusion Criteria:

DISEASE CHARACTERISTICS:

• Diagnosis of breast cancer

• Tissue samples available

• Samples are selected based on presence or absence of tumor receptors, (i.e.; estrogen, progesterone, and HER2 receptors) and grouped into following 4 categories:

  • Estrogen receptor (ER)-positive/progesterone receptor (PR)-positive/HER2-negative
  • ER-positive/PR-positive/ HER2-positive by FISH
  • ER-negative/PR-negative/HER2-positive
  • ER-negative/PR-negative/HER2-negative(triple negative or basal-type cancers)

PATIENT CHARACTERISTICS:

• Menopausal status not specified

PRIOR CONCURRENT THERAPY:

• Not specified

Exclusion Criteria:

• There are no exclusion criteria in this protocol

Previously collected breast cancer tissue samples (paraffin embedded blocks) and normal adjacent tissue are used for immunohistochemistry studies of expression of candidate genes.