Free Circulating Tumor DNA as a Diagnostic Marker for Breast Cancer

Background Cell-free DNA (cfDNA) in the plasma of patients with both malignant and benign breast lesions was analyzed to determine whether the findings may have diagnostic and prognostic implications and to analyze the association between the levels of cfDNA and prognostic parameters. Methods Plasma samples were obtained from 99 subjects; 42 with breast cancer (BC), 30 with benign breast lesions, and 27 healthy women as normal controls. Circulatory cfDNA was extracted from the plasma samples and quantified using a real-time quantitative PCR method. Immunohistochemistry was done on formalin-fixed paraffin-embedded sections to evaluate the status of hormonal receptors (estrogen receptor [ER] and progesterone receptor [PR]), and the protein expression of both Her2/neu and Topoisomerase IIa. Results The level of cfDNA in the BC group was significantly higher than in the benign lesions and control groups. cfDNA level was associated with malignant tumor size, lymph node involvement, stage, and grade as well as Her2/neu and Topoisomerase IIa expression, while it was not associated with ER or PR status. Conclusions The present study suggests that the level of cfDNA can be easily quantified using plasma samples. Thus, level of plasma cfDNA might constitute an important noninvasive diagnostic and prognostic valuable tool in cancer breast patients management. J. Clin. Lab. Anal. 26:467-472, 2012. (C) 2012 Wiley Periodicals, Inc.