Breast Cancer, Tamoxifen, and the CYP2D6 Gene

Big news for breast cancer patients on tamoxifen. Ryan Phelan and Jason Bobe of DNA Direct were at the FDA meeting on October 18th where it was decided that information about the cytochrome P450*2D6 (CYP2D6) gene should be included on the package insert and drug label.

From DNA Direct affiliate company Genes and Drugs:

The 2D6 gene is involved in the metabolism of many drugs, including some over-the-counter medications. Different people have different variations of this gene. Some variations metabolize 2D6 drugs very quickly, while others don’t metabolize them as well. Still others don’t metabolize them at all. Knowing your genetic status may be useful to you in the future, should you be prescribed or consider taking other medications that are processed by 2D6.

Those who are slow metabolizers–between 7% to 10% of women diagnosed with breast cancer–face a higher risk of recurrence and should perhaps consider other treatments. According to Genes & Drugs, the 2D6 gene is involved in the metabolism of about 25% of commonly prescribed drugs, including codeine, so knowing your CYP 2D6 genotype may be beneficial for more people than just breast cancer patients.

Genes & Drugs* is offering genetic testing for 2D6 for $300. I’d like to know how many women will avail themselves of testing and how many doctors will be informing their patients about the potential benefits of genetic testing. If I were a breast cancer patient, I’d want to know my 2D6 genotype. Wouldn’t you?

More from Kaiser Daily Women’s Health Policy.

*Yes, I consider the folks at DNA Direct to be friends and have displayed an ad for them here at Genetics and Health before. But this post was NOT paid for nor sponsored in any way.