Positive correlation of cell-free DNA in plasma/serum in patients with malignant and benign breast disease

Background: Circulating cell-free (ccf) DNA is measurable in healthy individuals and in higher concentration in patients with benign and malignant breast disease (BD). Patients and Methods: In paired plasma and serum samples ccf DNA was extracted and quantified by real-time quantitative PCR for the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene. Results: The concentration of ccf DNA in serum was higher in patients with benign and malignant BD (p = 0.023/p = 0.001) compared to healthy controls, whereas ccf DNA in plasma was higher in patients with malignant BD compared to patients with benign BD or healthy controls (p = 0.012/0.007). The ccf DNA correlated significantly between plasma and serum samples inpatients with benign (p =0.01; R: 0.677) as well as malignant BD (p=0.01; R:0.713). Conclusion: The positive correlation between ccf DNA in plasma and serum in patients with benign as well as malignant BD, might have a diagnostic value for discriminating between malignant and benign BD.