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Updated: Jun 10, 2026
Serum and Plasma Copy Number Detection Using Real-time PCR
Published on: December 15, 2017
Serum free circulating DNA is a useful biomarker to distinguish benign versus malignant prostate disease
Edna Gordian1, Kavitha Ramachandran, Isildinha M Reis
1Sylvester Comprehensive Cancer Center, University of Miami School of Medicine, 1475 N.W. 12th Avenue, Miami, FL 33136, USA.
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.
