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Testing for Drug Response

Related Genetic Tests

Tamoxifen Response

Includes a personalized report, a letter for your doctor, and toll-free support

Price: $300.00

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Drug Response Test Finder

Over half of all medications are affected by 3 genes that you can test for: CYP 2D6, 2C9 and 2C19. This tool to see which drugs are affected by these genes.

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TAMOXIFEN RESPONSE TESTING

What Is Tamoxifen?

Tamoxifen (brand name: Nolvadex) is a medication used to treat patients with breast cancer as well as people who are at high risk for breast cancer. It can also be used to treat other kinds of cancers.

Tamoxifen works by interfering with the activity of the hormone estrogen, which feeds the growth of many, but not all breast cancers. Tamoxifen binds to the estrogen-receptor sites in breast cells and prevents estrogen from binding to them. Because tamoxifen works against the effects of estrogen in the breast, it functions as an "anti-estrogen" in breast tissue.

For people with advanced breast cancer, tamoxifen is used to slow or stop the growth of cancer cells that are present in the body. For people with early stage breast cancer, tamoxifen is used as an additional treatment (adjuvant therapy). It helps prevent the original breast cancer from returning, and it helps prevent the development of new breast cancers.

For women who have not had breast cancer but are at high risk (women who carry a mutation in the breast cancer genes BRCA1 or 2, women who have a significant family history of breast cancer, and women who have precancerous lesions including atypical ductal and lobular hyperplasia and lobular carcinoma in situ) tamoxifen can be used to reduce their chance of developing the disease.

Tamoxifen is only effective, however, if the body can properly metabolize it. A small percentage of people carry a common genetic variation that prevents them from metabolizing tamoxifen and converting it to its active form. Recently, a genetic test has been developed that can identify who these people are.

For more information about tamoxifen, you can read the National Cancer Institute's Tamoxifen Fact Sheet.

Next Article: Hormonal Therapy