Press Room

Study Links HOXB13 & IL17BR with Estrogen Signaling in Breast Cancer

Biomarkers Used to Predict Endocrine Responsiveness in ER-Positive Patients

CARLSBAD, CA (November 29, 2007) — AviaraDx, Inc. today announced the publication of a study that provides further insight into the underlying biology of the company’s H/I™ (HOXB13/IL17BR) test, which identifies estrogen receptor (ER)-positive, node-negative breast cancer patients who have a significantly increased risk of cancer relapse when treated with standard endocrine therapy.

The study, “The Prognostic Biomarkers HOXB13, IL17BR, and CHDH Are Regulated by Estrogen in Breast Cancer,” was published in the November 1, 2007, edition of Clinical Cancer Research. The results are based on an analysis of 75 ER-positive and 73 ER-negative primary breast tumor samples from Massachusetts General Hospital. 

The analysis concluded that HOXB13 (a gene that regulates normal development and cellular differentiation) and IL17BR (a cytokine receptor that indicates estrogen sensitivity) are regulated by estrogen signaling.  In the breast tumor samples studied, HOXB13 expression was negatively correlated while IL17BR expression was positively correlated with estrogen receptor status. In ER-positive breast cancer cells, estrogen suppresses HOXB13 expression and stimulates IL17BR expression, resulting in a low expression ratio of HOXB13:IL17BR (H/I). A high ratio of H:I in ER-positive tumors indicates a state of dysfunctional ER signaling, which may lead to resistance to endocrine therapy.

The study also found that the expression of both genes is correlated with HER2 status, a known negative predictor of endocrine treatment response, in a different manner than other well-known ER-regulated genes such as PR and pS2. Together, these new findings suggest that HOXB13 and IL17BR represent a new class of biomarkers for determining ER function in breast cancer. 

“This is the first study which links the HOXB13 and IL17BR biomarkers to estrogen signaling,” said Dennis C. Sgroi, Director of Breast Pathology at Massachusetts General Hospital and Associate Professor of Pathology at Harvard Medical School, one of the study’s authors.  “That in turn leads to the hypothesis that dysfunctional estrogen signaling is involved in patients with ER-positive breast cancer who are resistant to anti-estrogen therapy, and it gives us a basis for further research into breast cancer behavior.”

“Our H/I test has been validated in multiple clinical studies with more than 2,300 patient samples. This most recent study offers an explanation for the biological mechanism behind our biomarkers,” said Antonius Schuh, Ph.D, Chief Executive Officer of AviaraDx.  “This is another important step in solving the clinical challenges of breast cancer treatment.”

AviaraDx’s H/I™ (HOXB13/IL17BR) test utilizes the HOXB13 and IL17BR gene-based biomarkers to evaluate the risk of recurrence and probable response to endocrine therapy in patients with ER-positive, node-negative breast cancer.  High levels of HOXB13 and low levels of IL17BR suggest that the patient will fail to respond or eventually develop resistance to endocrine therapy, enabling clinicians to potentially recommend more aggressive treatment regimens. 

In the U.S. approximately 100,000 women present with ER-positive, node-negative breast cancer every year. When treated with endocrine therapy alone after surgery, they face an average recurrence risk of 20% over a period of 15 years. The H/I test provides objective information to better assess the individual recurrence risk of an ER-positive, node-negative patient.

About AviaraDx, Inc.
AviaraDx discovers, develops, and commercializes new molecular diagnostic tests in oncology, enabling physicians to personalize cancer treatment through better understanding of the molecular biology underlying a patient's tumor.  The company’s current offerings include a molecular cancer classification assay, CancerTYPE ID™ capable of classifying 39 tumor types, H/I™ to predict endocrine response in breast cancer, and a molecular grade index (MGI) that utilizes a 5-gene biomarker to objectively measure tumor grade.  Additional tests for prostate cancer prognosis and prediction of tumor response to targeted therapies are in development.  AviaraDx offers these diagnostic tests to qualified physicians or laboratories through its CLIA-certified, CAP accredited laboratory service operations.  For more information, visit www.aviaradx.com.

PRESS CONTACT:
Steve Simon
847/415-9347

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