Study of Tumor and Blood Samples From Postmenopausal Women With Primary Breast Cancer Enrolled on Clinical Trial CAN-NCIC-MA27

DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed invasive breast cancer

  • Complete resection of primary tumor
  • Stage I-III (T1-3, N0-3, M0) disease
• Enrolled in clinical trial CAN-NCIC-MA27.
• No locally recurrent or metastatic breast cancer

• Hormone receptor status:

  • Estrogen receptor- or progesterone receptor-positive disease

PATIENT CHARACTERISTICS:

• Postmenopausal status, defined as one of the following:

  • At least 60 years old
  • Age 45-59 years with spontaneous cessation of menses for > 12 months prior to chemotherapy or study randomization
  • Age 45-59 years with cessation of menses for < 12 months or secondary to hysterectomy AND a follicle-stimulating hormone (FSH) level in the postmenopausal range (or > 34.4 IU/L)
  • Age 45-59 years on hormone replacement therapy (HRT) and discontinued HRT at diagnosis of breast cancer AND FSH level in the postmenopausal range (or > 34.4 IU/L)
  • Bilateral oophorectomy

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics