Diagnostic relevance of plasma DNA and DNA integrity for breast cancer.

Levels of ALU 115, ALU 247, DNA integrity ([1, 2]) and of the tumour markers CA 15-3 and CEA were analysed in the blood of 152 patients. Plasma levels of ALU 115 and ALU 247 were significantly higher in patients with locally confined (LBC; N = 65), metastatic breast cancer (MBC; N = 47), and benign diseases (N = 12) than in healthy controls (p < 0.001 for all comparisons). DNA integrity, CEA, and CA 15-3 were significantly higher in MBC than in benign controls and LBC but could not identify LBCs. The best discrimination of LBC from healthy controls was achieved by ALU 115 and ALU 247 (AUC 95.4 and 95.5 %) and of MBC from all control groups by CA 15-3 and CEA (AUC 83.2 and 79.1 %). Plasma DNA is valuable for the detection of LBC, while established tumour markers are most informative in MBC.