Breast Cancer is found to be one of the leading causes of death among Hispanic women and various reports reveal that breast cancers are more aggressive in the Hispanic population. The study of the role of genes and its effect on the activity of drugs began when two distinct reactions were observed on administration of a probe drug within the Hispanic group. While some people were able to metabolize the probe drug, some people developed indications of not being able to metabolize the drug at all. This began the study of the prominent role that genes play in drug metabolism.

CYP2D6 is a group of liver enzymes which have been found to metabolize or break down 25% of all clinically available medications. The CYP2D6 gene located on Chromosome 22 is responsible for the production of this enzyme in our body. A wide spectrum of drugs employed in the treatment of cancer are metabolized by this enzyme. The most relevant medication for breast cancer is Tamoxifen and has been used for many years as an endocrine treatment for hormone-positive breast cancer with indications in the metastatic, adjuvant and preventive settings. The lower level of toxicity in Tamoxifen treatments when compared to chemotherapy helps patients maintain quality of life and delay the use of cytotoxic treatments (causing destruction of cells) for as long as possible.

Tamoxifen is metabolized by the enzyme CYP2D6 and it is converted into its active form called Endoxifen which then acts on the body. However the CYP2D6 gene exhibits variability across population and among various ethnic groups. This results in variations in the levels of CYP2D6 enzyme in the body which leads to the difference in a person's ability to react to the drug, Tamoxifen. Variability ranges from Poor Metabolizers who have zero enzyme levels to Ultra-rapid Metabolizers who have very high levels of the enzyme in the body.

Recent research shows that 5-10% of Hispanic women are Poor Metabolizers. They are characterized by slower metabolism of the drug, due to the absence of adequate quantities of the enzyme. This might result in the build-up of Tamoxifen as the body lacks an efficient mechanism to eliminate the drug. Overall the slower metabolism of Poor Metabolizers may have a cascade effect when multiple concomitant medications that are metabolized by the CYP2D6 enzyme are administered, increasing the potential for Adverse Drug Reactions. Poor Metabolizers may thus be recommended to switch to an alternate method of treatment as they lack the ability to convert Tamoxifen into its active form, Endoxifen. They have been shown to have about three-fold risk of relapse than normal metabolizers.

Ultra-rapid Metabolizers constitute another 5% of the Hispanic population. They are characterized by higher than normal conversion of Tamoxifen to its active form, Endoxifen which results in high therapeutic effect of the drug. Although this population can experience the same benefit from a lower than standard dose of the drug, they face the possibility of serious side effects.

Genetic testing has been recently recommended by the FDA resulting in a label change for Tamoxifen which plays an important role in preventing the recurrence of breast cancer. Accredited DNA testing laboratories like Genelex offer tests on receipt of a physician prescription and delivers secure customized reports on the effect of your genes on the drugs.

Visit http://www.tamoxitest.com for more information on Tamoxifen testing.

Article Source: http://EzineArticles.com/?expert=Sruti_Mohandas