Tamoxifen is a medication for the treatment of breast cancer or for people at a high risk of developing breast cancer.
Recent research has shown that women with breast cancer may not receive the full medical benefit from taking tamoxifen due to their unique genetic make-up.[21] These women have a version of a gene called Cytochrome P450 2D6, which reduces the effectiveness of tamoxifen and increases their chance of breast cancer recurrence.
Genetic testing can tell whether tamoxifen is likely to be an effective treatment for you. This test looks at a specific gene, called CYP2D6, to determine whether your body can fully metabolize tamoxifen to its active form, endoxifen. If tamoxifen is not an effective treatment, your physician may recommend aromatase inhibitors.
Who Should Be Tested
The CYP2D6 test for tamoxifen is considered appropriate for women who are taking tamoxifen to treat breast cancer or for those considering taking tamoxifen to prevent the recurrence of breast cancer. It is especially important if the patient is also taking or considering co-administration with selective serotonin reuptake inhibitors (SSRIs).