Breast cancer laboratory tests
The goals of breast cancer testing are to identify genetic risk in high risk women, detect and diagnose breast cancer in its earliest stages, determine how far it has spread, evaluate the cancer's characteristics in order to guide treatment, monitor the effectiveness of treatment, and monitor the person over time to detect and address any cancer recurrences. The tissue samples required for some of the tests may involve a needle biopsy, in which cells from the breast are aspirated through a needle into a syringe, or by surgically removing some breast tissue or a tumor (open biopsy)
Laboratory tests for breast cancer can be broken down into groups, based on the purpose of testing:
- To determine genetic risk in high risk women: blood testing for mutations that may be present in the BRCA-1 and BRCA-2genes
- To diagnose: cytology - a microscopic examination of tumor cells obtained through fine needle aspiration and surgical pathology - a microscopic examination of tissue sampling via biopsy
- To determine treatment options: evaluation of the tumor's HER-2/neugene amplification status and estrogen and progesterone receptor status
- To monitor treatment and for recurrence: measurement of CA 15-3 or CA 27.29 in the blood
Some tests for breast cancer are performed on the woman's blood; others are done on a sample of cells or the tumor tissue.
Tests for Breast Cancer
| TEST | DESCRIPTION | TEST SAMPLE |
| BRACA-1/BRACA-2 | Genetic markers, if present, suggest an 80% likelihood of breast cancer occurrence. | Blood |
| Her 2/neu | A test for specific proteins; tumors with increased levels may respond well to a medication called Herceptin. | Tissue |
| Her-2/neu(blood) | After an initial diagnosis of metastatic breast cancer is made, this blood test may be performed and, if the initial level is greater than 15 ng/mL, then the test may be used to monitor treatment. | Blood |
| Estrogen Receptor/Progesterone Receptor | Increased levels suggest a good response to hormonal therapy. Hormonal therapy is not the same as hormone replacement therapy (HRT) and presence of these receptors does not indicate that HRT caused the cancer. | Tissue |
| CA15-3/ CA27.29 | Elevated blood levels of cancer antigens may indicate recurrence of cancer. | Blood |
| Oncotype DX | May assist in determining risk of recurrence and predict who will benefit from hormone therapy or chemotherapy. | Tissue |
| MammaPrint | May assist in determining whether a woman is at risk of recurrence of cancer, to help guide treatment. | Tissue |