The New York Times writes about the frequent inaccuracy of a test to detect certain proteins in breast tumors, which determines whether the patient will get Herceptin, a potent breast cancer treatment. "Drugs aimed at disabling proteins that spur cancer are, many oncologists say, the future of cancer therapies. ... But these so-called targeted therapies are only as good as tests to find their protein targets. And while most patients do not yet know it, those tests can be surprisingly unreliable." And "the problem continues to grow... 
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