The Iverson Tamoxifen panel has the capability to detect 16 significant genetic variants of CYP 450 2D6.  This information may help health care providers make more informed choices for treatment options and the prevention of breast cancer.

Tamoxifen and Breast Cancer

• Cytochrome P450 enzymes are a family of functional proteins encoded by 60 genes and play a crucial role in the metabolism of drugs. Almost every drug is processed by some of these enzymes.
• CYP450 2D6 is a metabolic liver-enzyme that biotransforms approximately 25% of known drugs metabolized by CYP enzymes. 2D6 is involved in the metabolism of xenobiotics and drugs and is responsible for more than 70 different drug oxidations.
• Many of these drugs are antipsychotic or antidepressant drugs, making 2D6 an important metabolic enzyme for psychiatry. Paroxetine and Fluoxetine (antidepressants) are classic drugs metabolized by 2D6.
• Approximately 11% of patients are heterozygotes and require reduced doses of anti-thrombolytics. 1:300 patients are slow hydroxylators (homozygous mutant) and may suffer from internal bleeding due to extremely high plasma concentrations of anti-thrombolytics.
• 7 - 10% of all Caucasians are poor metabolizers and may suffer toxicity from normally prescribed doses. 2D6 is probably the most well-studied P450 with a drug metabolism polymorphism.

• Approximately 7 - 10% of Caucasians are poor metabolizers of drugs metabolized by CYP2D6.

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7. Sachse, C et al., Cytochrome P450 2D6 variants in a Caucasian population: allele frequencies and phenotypic consequences. Am J Hum Genetics 1997; 60:284-295.