Biomarkers Wanted

The hunt for molecular signposts of disease in easy-to-sample blood and urine shows no sign of abating. But this year saw disappointing results for these so-called biomarkers. John P. A. Ioannidis of Stanford University School of Medicine and Orestis A. Panagiotou of the University of Ioannina School of Medicine, in Greece, reported that 35 highly cited biomarker-disease associations turned out to be lower than had been reported in initial studies (C&EN, June 6, page 38; J. Am. Med. Assoc., DOI: 10.1001/jama.2011.713). In addition, the National Cancer Institute’s Early Detection Research Network released its evaluation of 35 ovarian cancer biomarkers (C&EN, July 25, page 40; Cancer Prev. Res., DOI: 10.1158/1940-6207.capr-10-0195). Many of these markers had been claimed to be better than CA125 (cancer antigen 125)—one of only two markers approved for monitoring ovarian cancer. But when they were tested in 180 disease and 660 control specimens, none of them turned out to be better than CA125. Researchers blame these disappointments on small, poorly designed initial studies that don’t pan out in larger, more difficult, and more expensive clinical validation studies. These scientists are now working to improve discovery studies so they can better identify molecules that really serve as biomarkers.