Nanotechnology based assays for validating protein biomarkers
When investigators first began looking into clinical proteomics, technical limitations meant they could only measure a few hundred proteins at once, while flawed data analysis usually yielded "biomarkers" that didn't turn out to reveal anything at all.Although there have been over 10,000 publications on biomarker discovery with proteomics, the U. Food and Drug Administration (FDA) has only approved a single proteomics-based diagnostic test.The classic approach to asking clinical questions with proteomics has been to look at tissue or body fluid samples from patients with a given disease, which is verified by pathology, and compare them to a control group."One of the critical issues is, of course, that measuring only a couple of hundred samples, control and case, would need to be done at a high enough throughput, and these measurements must be reproducible," says Ruedi Aebersold, a professor of systems biology at the Swiss Federal Institute of Technology in Zurich.Testing breast tumors for certain cell surface receptors is now a routine part of cancer treatment.Patients with the HER2/neu receptor, for example, tend to have a more aggressive disease and will be given the targeted drug Herceptin."The conventional mass spectrometry technologies have great difficulty achieving these goals." And some say that testing hundreds of samples won't be enough.
Rather than just incrementally better, can you do better than ELISA?Targeted proteomics is homing in on promising biomarkers to help screen for cancer and guide patient treatment, but much work still needs to be done to validate these biomarkers and develop technology capable of bringing them to the clinic.By Anne Harding Inclusion of companies in this article does not indicate endorsement by either AAAS or nor is it meant to imply that their products or services are superior to those of other companies."It might be tumor tissue itself or fluid that arises from the tumor, but isn't diluted as it would be in the blood." He is currently looking at fluid from ovarian cysts, which potentially contain cancer-related proteins at a thousand-fold higher concentration than plasma.Many investigators, including Skates, use fractionation to look at less abundant proteins; yet another strategy is to deplete higher abundance proteins from a sample.
Tumors that carry estrogen receptors—about 70 percent of all breast cancers—will respond to tamoxifen and other selective estrogen receptor modulators.