Posted 1/6/2012 3:24 AM (GMT 0)
Sorry, bad link... I don't have an acct either...in any event:
January 5, 2012 — A cloud has descended over research into a biomarker for prostate cancer — early prostate cancer antigen-2 (EPCA-2) — which was described as "amazing" and appeared to overcome some of the shortcomings of prostate-specific antigen.
A paper about the biomarker was published several years ago in Urology (2007;69:714-720), but was retracted in October 2011 because data from the study could not be verified. "The article contains findings that may be unreliable," the study authors write in their retraction.
The move was highlighted in the Retraction Watch blog.
The paper's lead author is Robert H. Getzenberg, PhD, director of research of the James Buchanan Brady Urological Institute and professor of urology at the Johns Hopkins University School of Medicine in Baltimore, Maryland.
Dr. Getzenberg holds a patent for the assay technology that detects EPCA-2. The patent is owned by the University of Pittsburgh and Johns Hopkins University and has been licensed to Onconome Inc. Dr. Getzenberg received research funding from Onconome, which, in 2009, sued him and the 2 institutions for scientific fraud.
Dr. Getzenberg at one time reportedly described EPCA-2 as "amazing" because of its very high sensitivity and specificity, according to Retraction Watch.
A critic of EPCA-2 said that he has attempted for some time to publish a letter in Urology on the shortcomings of the assay used by Dr. Getzenberg and colleagues in their EPCA-2 research.
"This letter was accepted for publication, but has never been published and the reasons for the delay not resolved," said Eleftherios Diamandis, PhD, from the Department of Laboratory Medicine and Pathobiology at the University of Toronto in Ontario, Canada, in an essay published in Clinical Chemistry last year.
Dr. Diamandis said that he knew that the assay used to detect EPCA-2 was not capable of its touted abilities "as soon as the first paper on EPCA-2 was published."
"By analyzing what we know about ELISA assay design and performance, I concluded that the assay would not be either a sensitive or a specific measure of any analyte present in serum at the low ng/mL concentrations," he writes.
When his letter languished at Urology, he turned to Clinical Chemistry to publish his insights.
In his essay, Dr. Diamandis frames the EPCA-2 debacle in a larger cultural context: few biomarkers are validated but many are touted as the next great thing.
"The literature is full of reports of high-profile papers that have reported excellent diagnostic discrimination between groups, but subsequent independent validation was a failure," he writes.
In most cases, various biases were critical factors, he says. One example is the nuclear magnetic resonance profiling of urine for cancer detection, which has failed repeated validation efforts.
Dr. Diamandis has commented on this issue in other papers. Last year in the Journal of the National Cancer Institute, he pointed out that that not a single new "major cancer biomarker" has been approved for clinical use in the past 2 decades, despite large amounts of funding and plenty of public-relations hype, as reported at the time by Medscape Medical News.s