The story of HER2 is well known. This growth factor receptor molecule is overactive in many breast cancers and is the target of Herceptin (trastuzumab), a drug that has contributed to major improvements in the treatment of those advanced cancers. A genetic test identifies tumors in women that are HER2-positive and good candidates for therapy with trastuzumab.
HER2 is also over-expressed in a very small number of ovarian cancers but its genetic cousin, HER3, has been estimated to be abnormal in 25 to 30 percent of ovarian tumors, says Joyce Liu, MD.
Building on promising results in animal studies, Dr. Liu is now working to test the effectiveness of a new HER3-inhibitor, MM-121, in a clinical trial. In 2010, Dr. Liu and colleagues showed that the drug, which turns down activity in the HER3 signaling pathway, slowed the growth of ovarian tumors in mice. In the current trial, women with breast and ovarian cancer whose tumors have become treatment-resistant are receiving the MM-121 antibody in combination with taxol chemotherapy.
Dr. Liu and her colleagues are also hunting for biomarkers that could be made into a test, helping identify which patients might benefit most from the treatment. In addition, she says, "our lab is investigating which molecular partners are involved with HER3 function and might contribute to the development of ovarian cancer."
Turning Point 2011
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