"The HOXB13 and IL17BR gene profile was previously discovered as a potential marker of relapse in hormone-receptor positive breast cancer treated with tamoxifen," says Matthew Goetz, M.D., who co-led the project with James Ingle, M.D. and Fergus Couch, Ph.D. "Our new study shows that the marker is only useful for identifying women with a higher risk in the setting of lymph node-negative breast cancer."
The study, which was conducted by researchers at Mayo Clinic, Harvard Medical School and Arcturus Bioscience, tested whether the expression levels of two genes within women with early stage breast cancer affected the outcomes of women with estrogen receptor-positive breast cancer. The research team examined tissue from 206 postmenopausal women enrolled in a prospective study conducted by the North Central Cancer Treatment Group (NCCTG). They tested the level of gene expression of HOXB13 and IL17BR from paraffin-embedded tumors and found that the 2-gene expression ratio was an independent marker of early breast cancer relapse or death in lymph node-negative breast cancer.
"We believe that these findings are clinically important and corroborate the accumulating laboratory data which suggests that the HOXB13 gene is critically involved in breast cancer metastases," says Dr. Goetz. "Further research is needed to determine whether more aggressive or additional treatments will improve the outcomes of women identified to be at high risk by means of this marker."
Breast cancer is diagnosed in approximately one million women each year, and claims the lives of over 40,000 in the United States. More than two-thirds of all breast cancers are hormone positive, and most of these are early stage (lymph node-negative).
Other Mayo Clinic researchers involved with this study (from the Rochester, Minn., and Jacksonville, Fla., sites) included: Vera Suman, Ph.D.; Andrea Nibbe; Daniel Visscher, M.D.; Carol Reynolds, M.D.; Wilma Lingle, Ph.D.; and Edith Perez, M.D. They collaborated with Dennis Sgroi, M.D., from Harvard Medical School; and Mark Erlander, Ph.D., and Xiao-Jun Ma, Ph.D., both from Arcturus Bioscience Inc., Mountain View, Calif.
This research was conducted in part through a National Cancer Institute (NCI) SPORE grant -- Specialized Programs of Research Excellence. In addition, it was supported by the NCCTG, Arcturus Bioscience, Inc., and additional grants from the NCI, the Department of Defense, the Susan G. Komen Breast Cancer Foundation and the Avon Foundation.
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