Clinicians will have a new prognostic tool in the battle against breast cancer, as Quest Diagnostics Incorporated has announced that it has introduced its newly developed test, the Breast Cancer Gene Expression Ratio, which can help physicians predict the risk of disease recurrence in women with estrogen receptor (ER)-positive, lymph node-negative breast cancer.
According to Quest Diagnostics, it is the first company to develop a breast cancer recurrence test based on licensed gene-expression profiling technology from AviaraDx Inc., a molecular cancer profiling company located in Carlsbad, California.
Launched at the San Antonio Breast Cancer Symposium, December 14 - 17, 2006, the Breast Cancer Gene Expression Ratio is based on the ratio of the expression of two genes: the homeobox gene-B13 (HOXB13) and the interleukin- 17B receptor gene (IL17BR).
In breast cancers that are more likely to recur, the HOXB13 gene tends to be over-expressed, while the IL-17BR gene tends to be under-expressed.
In an 852-patient retrospective study published recently in the Journal of Clinical Oncology, it was found that the HOXB13:IL17BR ratio (H:I expression ratio) independently predicted breast cancer recurrence in patients with ER-positive, lymph-node negative cancer.
The H:I expression ratio was found to be predictive in patients who received tamoxifen therapy as well as in those who did not.
The clinical value of the Breast Cancer Gene Expression Ratio also is supported by a study published earlier this year in Clinical Cancer Research. The study found that a high H:I expression ratio is associated with an increased rate of relapse and mortality in ER-positive, lymph node- negative cancer patients treated with surgery and tamoxifen.
According to the American Cancer Society (ACS), more than 210,000 cases of breast cancer are diagnosed annually in the United States. Data from the National Cancer Institute and ACS indicate that approximately half of these cases -- about 100,000 women -- are diagnosed with ER-positive, node-negative cancers (3). It is this group of patients who may benefit from H:I testing.
"Until recently, a patient's breast cancer prognosis depended on limited variables, such as tumor size and grade, patient age, lymph node involvement and hormone-receptor status," explains Richard A. Bender, M.D., F.A.C.P, Quest Diagnostics' Medical Director for Oncology.
"With the H:I measurement, we now have more information to help predict the likelihood of disease recurrence in patients with ER-positive, node-negative breast cancers. Physicians and patients will want to consider this new information when deciding on treatment options."
Quest Diagnostics will provide Breast Cancer Gene Expression Ratio testing to physicians through Quest Diagnostics Nichols Institute, the company's esoteric testing laboratory in San Juan Capistrano, California, which has validated the test.
"The Breast Cancer Gene Expression Ratio represents a significant advance in personalized medicine in oncology," says Antonius Schuh, Ph.D., Chief Executive Officer of AviaraDx Inc., the company that discovered and validated the molecular markers used in the index.
"As we identify prognostic biomarkers in tumor types, we can further pinpoint and classify cancers so clinicians can appropriately benefit from the promising new targeted cancer therapies and make treatment decisions that may yield optimal outcomes for their patients."