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

You may be eligible if

• 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