Recent research on tamoxifen has shown that up to 7-10% of women with breast cancer may not receive the full medical benefit from taking tamoxifen, because of their unique genetic make-up. These women have a special version of a gene called 2D6, which may reduce the effectiveness of tamoxifen and increase their chance of breast cancer recurrence.

A simple and painless test for 2D6 genes is available from DNA Direct.