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• Available cancer biomarkers are associated with low diagnostic performance. • Satellite 2 DNA amount is higher in the blood circulation of patients with cancer. • Satellite 2 DNA may be a universal biomarker for the detection of cancer. Currently, cancer biomarkers are associated with low diagnostic performance, and the notion of using cell-free DNA (cfDNA) as a surrogate cancer biomarker is a subject of ongoing research efforts. Pericentromeric satellite repeats were shown to expand in tumor cells. Here, we hypothesized that the increased release of satellite DNA into the circulation might be a basis for developing a biomarker for the detection of cancer. The study included patients with different cancer types, and controls without cancer. Human satellite 2 repeat (HSATII) from chromosomes 1, 10, or 16 was amplified using extracted DNA from plasma or direct application of diluted plasma in PCR. We first showed that HSATII DNA levels were higher in patients with cancer than in controls relative to LINE1 element, with chr10-HSATII being the most relevant. Absolute quantification in digital PCR showed much higher levels of chr10-HSATII in patients with breast cancer compared with healthy individuals. Subsequently, employing diluted plasma also revealed that HSATII DNA was present in increased levels in patients with cancer including breast, gastric, lung or bile cancers, sarcoma or Hodgkin's lymphoma than in controls with an AUC of 94% in the ROC curve. This proof-of-concept study reveals the high potential of HSATII DNA as a surrogate cancer biomarker. [ABSTRACT FROM AUTHOR]

Abstract: Background: In breast cancer patients undergoing neoadjuvant chemotherapy before surgery, biomarkers for predicting response to therapy are urgently required. Patients and methods: In 65 patients with locally confined breast cancer who had completed the course of chemotherapy until surgery, plasma DNA biomarkers obtained before and during therapy were evaluated concerning (early) estimation of therapy response. Levels of repetitive ALU 115 and ALU 247 elements as well as DNA integrity calculated according the formulas of Umetani (1) and Wang (2) were correlated with changes in histopathological staging at surgery and compared with conventional tumor markers CEA and CA 15-3. Results: At surgery, 13 patients presented complete remission (CR), 32 partial remission (PR) and 20 no change of disease (NC). Pretherapeutic Her2/neu status was positively correlated with therapy response (p =0.019). DNA biomarkers before onset of therapy cycles 1, 2 and 6 did not indicate outcome after therapy. However, kinetics of ALU 115 from cycle 1 to 6 showed decreases in CR patients, while in NC patients, an increase was observed (p =0.033). Similar tendencies were found for ALU 247 fragments. DNA integrity index as well as CEA and CA 15-3 were not informative for therapy outcome. Conclusion: Kinetics of plasma DNA (ALU 115) is associated with response to neoadjuvant chemotherapy in patients with locally confined breast cancer. [Copyright &y& Elsevier]

Abstract: Extracellular nucleic acids are present in plasma, serum, and other body fluids and their analysis has gained increasing attention during recent years. Because of the small quantity and highly fragmented nature of cell-free DNA in plasma and serum, a fast, efficient, and reliable isolation method is still a problem and so far there is no agreement on a standardized method. We used spin columns from commercial suppliers (QIAamp DNA Blood Midi Kit from Qiagen; NucleoSpin Kit from Macherey-Nagel; MagNA Pure isolation system from Roche Diagnostics) to isolate DNA from 44 plasma samples in parallel at laboratories in Berlin and Munich. DNA in all samples was quantified by real-time PCR on a LightCycler 480 using three different targets (GAPDH, ß-globin, ERV). The quantities of cell-free DNA for the different isolation methods and genes varied between medians of 1.6ng/mL and 28.1ng/mL. This considerable variation of absolute DNA values was mainly caused by the use of different isolation methods (p<0.0001). Comparable results were achieved by the use of the genes GAPDH and ERV while higher values were obtained by use of ß-globin. The laboratory site had only minor influence on DNA yield when manual extraction methods were used. [Copyright &y& Elsevier]