Predicting Genetic Risks in Breast Cancer: BRCA-1 and BRCA-2 Mutations

Dr Vinay Bhatia, Assistant Manager – Molecular Biology

Rekha, a 50 year old mother of two, discovered a lump in her breast during self-examination. After completing a careful medical history and physical examination with her physician, a mammogram showed a suspicious lump. A biopsy from the lump indicated breast cancer. The tumor was tested for hormone receptors and for a growth-promoting gene and protein called HER-2/neu. The results pointed to a potentially aggressive tumor (HER2 positive). A PET scan combined with CT confirmed metastasis. To complete her evaluation, laboratory tests, including serum tumor markers (CEA and serum HER-2/neu), and additional blood tests, including CBC were done.

Rekha and her physician decided on a treatment course that included biological therapy to specifically prevent HER-2/neu cancer cells from growing. Her serum tumor markers were serially monitored to help track treatment efficacy. With the treatment, the levels of Rekha’s serum tumor markers dropped. Rekha’s ongoing care includes a combination of serial serum prognostic tumor-marker tests and non-invasive imaging studies. Concerned that her daughter might have a genetic predisposition for breast cancer, Rekha asked for a referral. A genetic specialist told Rekha that genetic test panels, combined with clinical data, could help assess her daughter’s risk many years before breast cancer could develop.

Rekha’s is a typical case, where the physician is usually consulted at an advanced stage of breast cancer, leading to a diagnostic dilemma that may affect treatment decisions. Breast cancer accounts for 23% of all cancer cases and is the most common cause of cancer in women. A woman has a 13% lifetime risk of developing invasive breast cancer, with more than one million women diagnosed with breast cancer every year in the world.

HOW IS BREAST CANCER DIAGNOSED IN A LABORATORY?

Tests and procedures used to diagnose breast cancer include:

Breast Exam: Examination of breast for any lumps or other abnormalities.

Mammogram: A mammogram is an X-ray of the breast. Mammograms are commonly used to screen for breast cancer. If an abnormality is detected on a screening mammogram, the clinician might recommend a diagnostic mammogram to evaluate that abnormality further.

Breast Ultrasound: Ultrasound uses sound waves to produce images of structures deep within the body. Ultrasound may help distinguish between a solid mass and a fluid-filled cyst.

Breast Magnetic Resonance Imaging (MRI): An MRI machine uses a magnet and radio waves to create pictures of the interior of your breast.

Biopsy: Imaging studies such as mammogram and MRI, often along with physical exams of the breast, can lead doctors to suspect that a person has breast cancer. However, the only way to know for sure is to take a sample of tissue from the suspicious area and examine it under a microscope. Biopsy samples are sent to a laboratory for analysis where experts determine whether the cells are cancerous. A biopsy sample is also analyzed to determine the type of cells involved in the breast cancer, the aggressiveness (grade) of the cancer, and whether the cancer cells have hormone receptors or other receptors that may influence the patient’s treatment options.

To know about different types of biopsy procedure and staging of breast cancer, click this link http://blog.oncquest.net/?p=67 .