Nanotechnology breakthrough could greatly enhance biomarker detection. Research conducted at Princeton University suggests that fluorescence signals far fainter than today's lowest limit may be able to be used to detect biomarkers in a range of tests. An immunoassay used to detect disease could be made more than three million times more sensitive, according to researchers who combined standard biological tools with a breakthrough in nanotechnology. The increased performance could greatly improve the early detection of cancer, Alzheimer's disease, and other disorders by allowing clinicians to observe far lower concentrations of telltale markers than was previously practical.
In conventional immunoassays, if the amount of biomarker is too small and thus the fluorescent light is too faint to be detected, evidence of disease cannot be discovered. The Princeton researchers used nanotechnology to greatly amplify faint fluorescence. By fashioning glass and gold structures so small they could be seen only with a powerful electron microscope, the scientists were able to dramatically increase the fluorescence signal compared to conventional immunoassays—up to a 3-million-fold improvement.
The key to the breakthrough lies in a new artificial fluorescence-enhancing nanomaterial called D2PA. When and if the new technology can be approved for laboratory use, the procedures involved in conducting immunoassays would remain unchanged.
New Studies
High accuracy reported for a genetic test for Down syndrome and Edwards syndrome. An international cohort study published in the American Journal of Obstetrics and Gynecology offers preliminary indications that a genetic test to screen pregnant women for fetal trisomy 21 (which results in Down syndrome) and fetal trisomy 18 (which results in Edwards syndrome) is highly accurate.
The trial evaluated a new noninvasive assay known as Digital Analysis of Selected Regions (DANSR). It analyzes fetal cell-free DNA, small DNA fragments which circulate in maternal blood. Unlike similar tests that analyze DNA from the entire genome, DANSR analyzes only the chromosomes under investigation for a more efficient and less expensive process. The results are evaluated with a novel analysis algorithm, the Fetal-fraction Optimized Risk of Trisomy Evaluation (FORTE), which considers age-related risks and the percentage of fetal DNA in the sample to provide an individualized risk score for trisomy detection.
Just over 4,000 pregnant women from the U.S., the Netherlands, and Sweden were enrolled in the study. Blood samples were taken before the women underwent invasive testing for any indication, and 774 samples were excluded prior to analysis. The classification of samples as High Risk or Low Risk using the DANSR and FORTE method was compared with the results from amniocentesis and CVS. The DANSR and FORTE method identified 100% of the 81 T21 cases as High Risk, and there was one false positive among the 2,888 normal cases. Of the 38 T18 cases, 37 were classified as High Risk, and there were two false positives among the 2,888 normal cases, for a sensitivity of 97.4% and a false positive rate of 0.07%.
Cancer
Clinical trials show promise in breast cancer treatment. Clinical trials of the drug trastuzumab emtansine (T-DM1), developed by Genentech, have shown promise in improving treatment outcomes for advanced HER2-positive breast cancer patients. The research, presented at the American Society for Clinical Oncology meeting last month is the most recent example of the antibody-drug conjugate approach, and perhaps the one with the most far-reaching implications yet. Treatment with the combination of the targeting drug trastuzumab (brand name Herceptin) and the chemotherapy drug emtansine, researchers say, is more successful than treatment with trastuzumab alone, and it can battle cancer after trastuzumab alone is no longer effective. Kimberly Blackwell, MD, the head study author, uses the analogy of a carrier pigeon to describe the way the two drugs work together: the trastuzumab zeroes in on the malignant cells and then delivers the DM1 drug to them. Since it is inactive until entering the tumor cell, the drug combination largely spares healthy cells, which greatly reduces side effects.
In the clinical trial, women who were treated with T-DMI averaged 9.6 months of survival without progression of the cancer, as opposed to an average of 6.4 months for a control group. Genentech, which developed the drug and sponsored the trial, plans to file for FDA approval before the end of the year. If approved, the drug will be the first based on this approach that has been approved for a common cancer.
Certification
“POCT Overview” added to AACC's professional certificate programs. The American Association for Clinical Chemistry, which will hold its annual meeting in Los Angeles July 15-19, has announced the launch of its Overview of Point of Care Certificate Program, supported in part by a grant from Abbott Point of Care. This eight-course, certificate-granting program was developed for healthcare professionals who are being asked to assume responsibilities for point-of-care testing (POCT). Given the dramatic increase of near-patient testing in today's healthcare environment, ensuring test quality outside of the core laboratory is vital for effective patient care and successful patient safety initiatives. These courses provide laboratory professionals with essential information in eight fundamental areas of POCT: Administration; Communication; Connectivity and IT; Education and Training; Instrument Selection and Validation; Policies and Procedures; Quality Management; and Regulations. For an overview, visit http://direct.aacc.org/productcatalog/product.aspx?id=6833
