Fluorouracil

DPD Enzyme Deficiency Test for Fluorouracil (5-FU)

Is your physician thinking of prescribing Fluorouracil (5-FU)?

Are you concerned about drug safety?

Fluorouracil (5-FU) is one of the most successful and widely used chemotherapy drugs. It is often used in the treatment for breast, colon, and skin cancer (three of the most frequently occurring cancers).

5-FU binds to an enzyme inside of cancer cells called Thymidilate Synthetase, and then exerts its anti-cancer effect on the cells. In general, 5-FU is relatively well tolerated at standard doses However, an estimated 3-8% of patients have a genetic variation that leads to a deficiency of an enzyme called Dihydropyrimidine dehydrogenase (DPD) that is crucial for the metabolism and deactivation of 5-FU. Patients with this variation have severe toxic reactions that may be fatal with even small doses and often the very first dose of 5-FU.

Who Should Be Tested

The DPD test for 5-FU is considered appropriate for any person who is taking or considering 5-FU based chemotherapy.

It is recommended that this screening be accompanied by direct measurement of DPD activity prior to 5-FU treatment in cancer patients. Although this test screens for the most frequent genetic variation that causes DPD enzyme deficiency this does not rule out the possibility of a decrease in DPD activity due to other factors or genetic variations.

The Testing Process

The process is simple. You can order testing directly if you have a physician prescription or your healthcare provider can request testing for you. We send a cheek swab collection kit with directions by mail. Use the return mailer to submit samples and receive results in ten days or less. Faster testing is available for an additional charge. Call a DNA testing consultant at (800) 523-3080 for details and to order.

Note: Testing is currently not available to New York residents and requires a prescription from a physician.