Many researchers believe that the emerging field of proteomics will revolutionize the way cancer and other major illnesses are detected. With the discovery of new proteins and the mapping of the human genome, proteomics may be the vanguard of a new generation of early detection tools and tailored therapy for individual patients.
Researchers from the U. S. Food and Drug Administration, the National Cancer Institute and the Lineberger Comprehensive Cancer Center at the University of North Carolina examined blood samples from 154 men with PSA levels between 2.5 ng (nanograms)/ml and 15 ng/ml or who had abnormal physical exams; such PSA scores generally place men at a higher than normal likelihood of having cancer. All of the men underwent a biopsy. The team retrospectively used sophisticated pattern-recognition algorithms to analyze the pattern of proteins in the participants' blood to determine if a biopsy had been necessary.
"We believe that proteomic profiling could save more than 50 percent of biopsies without missing more than 5 percent of cancers," according to David Ornstein, M.D., currently assistant professor of urology, University of California at Irvine, and lead investigator of the study.
Researchers used serum samples from 63 men (23 with two or more negative biopsies; 10 with one negative biopsy; and 30 with biopsy-detected prostate cancer) to train the testing algorithm to discriminate between cancerous and non-cancerous cells based on the pattern of certain proteins. When they blindly tested the remaining 91 samples (28 with prostate cancer; 63 with one or more negative biopsies) they yielded a sensitivity of 100 percent and specificity of 67 percent.
"We hope this could lead to a refinement of the PSA testing so that we could make a more accurate prediction of cancer and reduce the number of unnecessary biopsies," according to Emanuel Petricoin, Ph.D., Co-Director, Laboratory of Immunology, Division of Therapeutic Proteins, Office of Therapeutics Research and Review, Center for Biologics and Research (CBER), FDA, and an investigator on the study. "Millions of men undergo biopsies, and only 30 percent really need them."
Scientists hope that proteomic pattern profiling can ultimately be used to determine which cancers need to be treated aggressively and which can be safely followed. The researchers have also used proteomic pattern profiling to distinguish ovarian cancer patients from healthy women. The method was also useful in identifying patients with early stage disease.
"Studies suggest we may be able to use this novel method to more accurately detect cancer," said Dr. Lance Liotta, Chief, Laboratory of Pathology, Center for Cancer Research (CCR), and an investigator on the study. "Additionally, we are finding other applications for proteomic testing, including patient response to standard treatments, which may have significant clinical implications for future research and development."
Prostate cancer is one of the most common cancers found in men today. The American Cancer Society estimates that in 2003 there will be about 91,800 new cases of prostate cancer in the United States, causing almost 29,000 deaths.
Founded in 1907, the American Association for Cancer Research (AACR) is a professional society of more than 20,000 laboratory and clinical scientists engaged in cancer research in the United States and more than 60 other countries. AACR's mission is to accelerate the prevention and cure of cancer through research, education, communication and advocacy. Its principal activities include the publication of five major peer-reviewed scientific journals (Cancer Research; Clinical Cancer Research; Molecular Cancer Therapeutics; Molecular Cancer Research; and Cancer Epidemiology, Biomarkers & Prevention). AACR's annual meeting attracts more than 12,000 participants who share new and significant discoveries in the cancer field, and the AACR's specialty meetings throughout the year focus on all the important areas of basic, translational and clinical cancer research.
Contact: Warren Froelich/AACR
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Aimee Frank/Spectrum Science
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