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Nucleosomes, complexes of DNA and histone proteins, are released during cell death into the blood circulation. Elevated serum and plasma levels have been found in various forms of cancer, but also in autoimmune diseases and acute situations such as stroke, trauma, and during sepsis. Here, the clinical relevance of circulating nucleosomes for diagnosis, staging, prognosis, and therapeutic monitoring of cancer is reviewed. Several studies have shown that levels of nucleosomes are significantly higher in serum and plasma of cancer patients in comparison to healthy controls. However, because of elevations of nucleosome levels in patients with benign diseases relevant for differential diagnosis, they are not suitable for cancer diagnosis. Concerning tumor staging, nucleosome levels correlate with tumor stage and presence of metastases in gastrointestinal cancer, but not in other tumor types. Prognostic value of circulating nucleosomes is found in lung cancer in univariate analyses, but not in multivariate analyses. Circulating nucleosomes are most informative for the monitoring of cytotoxic therapy. Strongly decreasing levels are mainly found in patients with remission of disease, whereas constantly high or increasing values are associated with progressive disease during chemo- and radiotherapy. In addition, therapy outcome is already indicated by the nucleosomal course during the first week of chemo- and radiotherapy in patients with lung, pancreatic, and colorectal cancer as well as in hematologic malignancies. Despite their non-tumor-specificity, kinetics of nucleosomes are valuable markers for the early estimation of therapeutic efficacy and may be helpful to adapting early cancer therapy in the future. [ABSTRACT FROM AUTHOR]

This study aimed to test the diagnostic utility of the DNA integrity index for detection of cancer. Matched serum and plasma samples of 42 patients with various forms of cancer and 17 patients with corresponding benign diseases were analyzed. DNA was isolated from 1 mL serum and plasma using the MagNA Pure LC system. Cell-free DNA was quantified by real-time PCR using the reference gene of the LightCycler t(14;18) kit. Subsequently, the DNA integrity index was calculated as the ratio in relative abundance of 347-bp versus 137-bp PCR products. We found that DNA concentrations were not different in plasma (median: 4.5 ng/mL) and serum (67.1 ng/mL) of patients with benign diseases when compared with values in plasma (5.1 ng/mL) and serum (65.4 ng/mL) of cancer patients. Similarly, the DNA integrity index in plasma (0.38), and serum of patients with benign diseases (0.29) was comparable to values in plasma (0.33) and serum (0.37) of cancer patients. Diagnostic sensitivity of DNA (AUC 0.53) and DNA integrity (AUC 0.45) was poor in plasma, and was increased only slightly by the combination of both (AUC 0.57). In serum, sensitivity of DNA (AUC 0.52) and DNA integrity (AUC 0.64) was higher and was further improved by the combination of both (AUC 0.72) reaching a sensitivity of 30% at 100% specificity. In conclusion, we could not confirm a high diagnostic utility of the DNA integrity index. However, a combination with other markers such as DNA may enhance sensitivity for cancer detection. [ABSTRACT FROM AUTHOR]

Facing an era of promising new antitumor therapies, predictors of therapy response are needed for the individual management of treatment. In sera collected prospectively from 311 patients with advanced non-small cell lung cancer receiving first-line chemotherapy, changes in nucleosomal DNA fragments, cytokeratin-19 fragments (CYFRA 21–1), carcinoembryonic antigen (CEA), neuron-specific enolase (NSE), and progastrin-releasing peptide (ProGRP) were investigated and correlated with therapy response. In univariate analysis, high levels, slower and incomplete decline in nucleosomal DNA, CYFRA 21–1, and CEA predicted poor outcome. DNA concentrations at day 8 of the first therapeutic cycle and CYFRA 21–1 before start of the second cycle were identified as best predictive variables. In multivariate analysis, they predicted progression with a specificity of 100% in 29% of the cases earlier than imaging techniques. Thus, nucleosomal DNA and CYFRA 21–1 specifically identify a subgroup of patients with insufficient therapy response at the early treatment phase and showed to be valuable for disease management. [ABSTRACT FROM AUTHOR]

The inadequate response of immune cells to circulating apoptotic products, such as nucleosomal DNA fragments, is assumed to be a potent stimulus for the production of autoantibodies during the pathogenesis and progression of systemic lupus erythematosus (SLE). Here, we analyzed the levels of circulating nucleosomes, caspases, and C-reactive protein in sera of 244 individuals with various autoimmune diseases (155 with autoimmune hepatic disorders, 25 with ANCA-associated vasculitis, and 64 with various connective tissue diseases), and 32 healthy controls. Nucleosomes and caspase activities were significantly elevated in sera of patients with hepatic autoimmune diseases, connective tissue diseases, and particularly in ANCA-associated vasculitis when compared with healthy individuals. Nucleosomes showed a correlation with caspases, and caspases with C-reactive protein, but nucleosomes did not correlate with C-reactive protein. Serum levels of the apoptotic products, nucleosomes, and caspases are increased in various autoimmune diseases but may not be solely responsible for antinucleosome antibody production in SLE patients. It remains to be clarified whether qualitative changes in nucleosomes are linked with pathogenesis and disease progression in SLE. [ABSTRACT FROM AUTHOR]