Amount of DNA in plasma and cancer risk: A prospective study

Abstract

Levels of plasma DNA concentrations in cancer patients have been shown to be higher than the plasma DNA concentrations found in healthy subjects. The value of plasma DNA levels for development of neoplastic or pulmonary disease was evaluated in a large prospective study. Plasma samples (n ‫؍‬ 1,184) were analyzed from 776 controls, 359 cases of cancer (lung, bladder, oral cavity, pharynx, larynx, leukemia) and 49 deaths from chronic obstructive pulmonary disease (COPD), including never smokers and ex-smokers, from 9 countries across Europe. The amount of plasma DNA was variable across the European Prospective Investigation into Cancer and Nutrition (EPIC) centers. High DNA concentrations in some centers might be due to the type of population recruited and/or the treatment of the samples. An elevated and statistically significant odds ratio (OR) was found for COPD deaths (OR ‫؍‬ 2.53; 95% CI ‫؍‬ 1.06-6.02), while nonsignificant increased ORs were present for oral cancers, cancers of the pharynx and larynx and leukemia. When the analyses were stratified by time since recruitment (below or above 36 months), the increased ORs were limited to the more recent period of recruitment, i.e., a time elapsed between blood drawing and disease onset lower than 36 months. This was particularly true for COPD deaths (OR ‫؍‬ 12.7; 95% CI ‫؍‬ 1.57-103) and leukemia (OR ‫؍‬ 2.37; 95% CI ‫؍‬ 1.20-4.67).

Optimizing the yield and utility of circulating cell-free DNA from plasma and serum

“…This contradicts the observations of Jung et al [28], who reported that the DNA concentration in plasma did not change when blood samples were stored at RT for 8 h, or at 4 o C for 24 h. These contradictory results might be due to sampling at only two time points (8 and 24 h) at 4 o C in their study. It is likely that the increased DNA levels found at 25h are attributable to contamination of plasma with genomic DNA from leukocyte lysis [3].…”

“…It is present in normal healthy individuals at low concentrations (ng/ml) [3]. Raised levels of CFDNA in cancer patients have been reported in many tunour types [2][3][4][5].…”

“…It is present in normal healthy individuals at low concentrations (ng/ml) [3]. Raised levels of CFDNA in cancer patients have been reported in many tunour types [2][3][4][5]. The finding that genetic and epigenetic changes typical of tumours can be detected in CFDNA from cancer patients, suggests that the excess CFDNA is of tumour origin.…”

Detection and characterization of circulating cell free tumor DNA in cancer patients with malignant solid tumors. Liquid biopsy: a new tool in molecular pathology?

“…It is known that cancer patients have higher cfDNA levels than healthy donors, however, the overall concentration of cfDNA varies considerably in blood samples in both groups [19][20][21][22][23]. An average of 180 ng cfDNA per mL of blood has been measured in cancer patients, whereas healthy individuals carry about 30 ng of cfDNA per mL of blood [24].…”

“…An average of 180 ng cfDNA per mL of blood has been measured in cancer patients, whereas healthy individuals carry about 30 ng of cfDNA per mL of blood [24]. A prospective study of cell-free DNA levels in plasma samples and their impact in cancer patients showed considerable variation between the European Prospective Investigation into Cancer and Nutrition (EPIC) centers [23]. It was discussed that this individual variation ( Figure 1) was due to the type of population and the treatment of samples.…”