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U.S. Department of Health and Human Services

Medical Devices

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Dako TOP2A FISH pharmDx™ Kit - P050045

This is a brief overview of information related to FDA’s approval to market this product. See the links below to the Summary of Safety and Effectiveness Data (SSED) and product labeling for more complete information on this product, its indications for use, and the basis for FDA’s approval.


Product Name: Dako TOP2A FISH pharmDx™ Kit
PMA Applicant: Dako Denmark A/S
Address: Produktionsvej 42, DK-2600 Glostrup, Denmark
Approval Date: January 11, 2008
Approval Letter: http://www.accessdata.fda.gov/cdrh_docs/pdf5/p050045a.pdf

What is it? TOP2A FISH pharmDx™ Kit is a laboratory test used to help a doctor assess the likely clinical course for certain patients with breast cancer. The test uses fluorescent DNA probes to measure the number of copies of the TOP2A (Topoisomerase 2 alpha) gene on chromosome 17 in breast cancer cells. The TOP2A gene plays a role in cell division. Changes in the number of copies of TOP2A gene indicate an elevated risk of post-surgical recurrence of the breast cancer or decreased long term survival.

How does it work?

  • A small sample is obtained from the patient’s breast cancer.
  • The sample is embedded in paraffin, and a thin slice is cut and attached to a glass microscope slide.
  • With special chemicals and heat treatment, a red fluorescent-tagged DNA probe binds to matching DNA of the TOP2A gene and a green fluorescent-tagged DNA probe binds to the matching central portion of Chromosome 17 in cells on the slide.
  • A trained medical professional, using a fluorescence microscope, checks the quality of the fluorescence signals, counts the number of red and green signals, and calculates the ratio of red to green signals.
  • The results are reviewed by a pathologist and reported to the ordering doctor.

When is it used? Breast cancer patients for whom menopausal status and tumor characteristics suggest a relatively high risk of cancer recurrence and who receive certain kinds of chemotherapy treatment.

What will it accomplish? The TOP2A FISH pharmDx™ test, when used with other clinical information and laboratory tests, may help a doctor in planning appropriate follow-up for a patient.

When should it not be used? Patients who have not been diagnosed with breast cancer, or whose menopausal status and breast tumor characteristics suggest a low risk of recurrence, or whose breast cancer is inoperable, or who do not receive one of the studied chemotherapy treatments.

Additional information: Summary of Safety and Effectiveness and labeling are available at: http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cftopic/pma/pma.cfm?num=p050045