Tamoxifen is used by breast cancer patients either to prevent cancer in high risk women or as a treatment option after chemotherapy and other procedures. Tamoxifen prevents the growth and multiplication of cancer cells by blocking the female hormone Estrogen.

Research suggested that 7-10% of women taking Tamoxifen have a genetic variation in a gene which prevents the action of Tamoxifen.

I found this website www.tamoxitest.com which describes a genetic test that uses a cheek swab sample. My friend took this test and was impressed by the result. The company Genelex based in Seattle which performed the testing also gave her a subscription to a software called GeneMedRx which can predict adverse drug reactions.

I hope this helps the rest of you too.