Author(s): Gordian E, Ramachandran K, Reis IM, Manoharan M, Soloway MS,
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Abstract BACKGROUND: Free circulating DNA (fcDNA) has been shown to be elevated in serum of prostate cancer patients compared with benign controls. However, studies evaluating the role of fcDNA as a biomarker in a "representative" patient group who have undergone prostate cancer screening are lacking. Our study examined the use of serum fcDNA levels as a biomarker of prostate cancer in such a setting. METHODS: The study included 252 men, with prostate-specific antigen (PSA) levels >4 ng/mL and/or abnormal digital rectal exam. fcDNA levels in serum before prostate biopsy were quantitated by real-time PCR amplification of the glutathione S-transferase, pi, gene. RESULTS: Patients with PSA < or = 10 ng/mL with fcDNA > 180 ng/mL were at increased risk for prostate cancer compared with those with fcDNA < or =180 ng/mL (odds ratio, 4.27; 95\% confidence interval, 2.05-8.88; P < 0.001; area under the curve, 0.742). The multivariate model including age, race, PSA, fcDNA, and interaction between fcDNA and PSA yielded a high negative predictive value of 93.1\% and increased specificity of 33.1\% compared with negative predictive value of 73.3\% and specificity of 6.7\% in the model excluding fcDNA. CONCLUSIONS: Our results indicate that fcDNA may improve the specificity of prostate cancer screening. IMPACT: Our study shows that adding fcDNA to prostate cancer screening can reduce the number of unnecessary prostate biopsies. (c)2010 AACR.
This article was published in Cancer Epidemiol Biomarkers Prev
and referenced in Journal of Molecular Biomarkers & Diagnosis