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FDA Approves New Genetic Test for Breast Cancer

January 20, 2008

First-of-its-kind product gives prognostic information and 
may help health care providers in deciding best follow-up 
options 
 
The U.S. Food and Drug Administration has approved a test 
that helps in assessing the risk of tumor recurrence and 
long-term survival for patients with relatively high-risk 
breast cancer. The TOP2A FISH pharmDx is the first approved 
device to test for the TOP2A (topoisomerase 2 alpha) gene 
in cancer patients. 
 
The TOP2A gene plays a role in DNA replication. The TOP2A 
FISH pharmDx test uses fluorescently labeled DNA probes to 
detect or confirm gene or chromosome abnormalities, a 
technology known as fluorescent in situ hybridization 
(FISH). 
 
The recurrence of cancer depends partly on certain genes 
whose activity may be altered by changes in the number of 
gene copies in the tumor. Changes in the TOP2A gene in 
breast cancer cells mean there is an increased likelihood 
that the tumor will recur or that long-term survival will 
be decreased. 
 
"When used with other clinical information and laboratory 
tests, this test can provide health care professionals with 
additional insight on the likely clinical course for breast 
cancer patients," said Daniel Schultz, M.D., director of 
FDA's Center for Devices and Radiological Health. "It can 
also provide valuable information to assist health care 
providers and patients in better understanding the biology 
of breast cancer disease." 
 
The test is suitable for breast cancer patients who are 
premenopausal or for whom tumor characteristics, such as 
tumor size or lymph node involvement, suggest a higher 
likelihood of tumor recurrence or decreased survival. 
 
The FDA reviewed evidence that the test has been properly 
validated for its intended use. 
 
The product was studied in Danish patients who were treated 
with chemotherapy after removal of a breast tumor. The test 
is conducted on a small piece of the removed tumor. The 
removed piece is stained with the FISH chemicals and 
studied under a microscope. 
 
The company submitted data from a study using tumor samples 
and clinical data from 767 patients with high risk tumors 
at 21 centers in Denmark. These studies confirmed that the 
test was useful in estimating time to local or distant 
recurrence and overall survival in women who received 
certain chemotherapy regimens assisting in the treatment of 
the disease. 
 
The product is manufactured by Dako Denmark A/S (Glostrup, 
Denmark). 
 
Source: FDA