Posted on March 8th, 2009 by
Oncotype DX®, a genomic test that predicts likelihood of chemotherapy benefit and risk of recurrence among women with early-stage breast cancer, also provides information about the estrogen and progesterone receptor status of breast cancers. These results were published in the Journal of Clinical Oncology.
The majority of breast cancers are hormone receptor-positive. These cancers are stimulated to grow by the circulating female hormones estrogen and/or progesterone. Treatment of hormone receptor-positive breast cancer often involves hormonal therapies that suppress or block the action of estrogen. These therapies include tamoxifen [Nolvadex®] as well as agents known as aromatase inhibitors. Tamoxifen acts by blocking estrogen receptors, whereas aromatase inhibitors suppress the production of estrogen in postmenopausal women.
In order to determine whether hormonal therapy is likely to benefit a particular woman, it is necessary to accurately assess the hormone receptor status of the cancer. Currently, the standard test for hormone receptor status uses a procedure known as immunohistochemistry (IHC). It’s possible, however, that newer types of tests may provide comparable information about hormone receptor status along with other information that’s useful for treatment planning.
Oncotype DX is a genomic test that that has been validated for use in women with newly diagnosed, Stage I or II, node-negative, estrogen receptor (ER)-positive breast cancer. Studies have also suggested that the test may be useful for women with node-positive breast cancer. The test predicts risk of cancer recurrence as well as likely benefit from adjuvant chemotherapy. It evaluates the activity of 21 genes from a sample of the patient’s cancer to determine the patient’s Recurrence Score. The Recurrence Score ranges from 0 to 100, with a higher score indicating a greater risk of recurrence.
In addition to guiding decisions about chemotherapy, recent results indicate that Oncotype DX also provides information about the hormone receptor status of breast cancer. These results were published in the Journal of Clinical Oncology. The study involved 776 women with breast cancer. Hormone receptor status was assessed by the standard method of IHC as well as by Oncotype DX.
These results suggest that Oncotype DX could be used in place of conventional IHC testing for breast cancer hormone receptor status.
 Albain K, Barlow W, Shak S et al. Prognostic and predictive value of the 21-gene recurrence score assay in postmenopausal, node-positive, ER-positive breast cancer (S8814,INT0100). Presented at the 30th Annual San Antonio Breast Cancer Symposium. San Antonio, TX, December 13-16, 2007. Abstract #10.
 Badve SS, Baehner FL, Gray RP et al. Estrogen- and progesterone-receptor status in ECOG 2197: comparison of immunohistochemistry by local and central laboratories and quantitative reverse transcription polymerase chain reaction by central laboratory. Journal of Clinical Oncology. 2008;26:2473-2481.
Related News: Oncotype DX™ Provides Information About Hormone Receptor Status of Breast Cancer (9/14/2007)
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