Circulating DNA is a non-invasive prognostic factor for survival in non-small cell lung cancer.

INTRODUCTION: Circulating plasma DNA is present in a considerably higher concentration in lung cancer patients than in controls. Conflicting data are reported about circulating DNA as a prognostic factor. The aim of this study was to prospectively analyse the relationship of circulating plasma DNA with overall survival (OS) of previously untreated non-small cell lung cancer (NSCLC) patients. METHODS: 46 untreated NSCLC patients and 21 controls with a follow-up time of 6.5 years were analyzed. Quantification of baseline circulating plasma DNA was performed by a real-time quantitative polymerase chain reaction (qPCR) targeting the human beta-globin gene. Survival analysis was performed using the Kaplan-Meier method and compared with a Cox-regression analysis. RESULTS: The median DNA concentration of the patients who died (87%) was significantly higher compared to the patients that survived at the end of follow-up (55ng/ml versus 23ng/ml, p=0.02). In patients with higher DNA concentration overall survival was significantly worse. In this study no relation of DNA concentration with tumour characteristics, age, gender or pulmonary inflammatory conditions was found. CONCLUSION: In this study a high circulating plasma DNA concentration at time of diagnosis in NSCLC patients was a prognostic factor for poorer survival. Circulating DNA may be used as a non-invasive biomarker to refine the prognostic profile in NSCLC patients.

Improved real-time detection of the H63D and S65C mutations associated with hereditary hemochromatosis using a SimpleProbe assay format.

BACKGROUND: Genetic predisposition to hemochromatosis involves several different point mutations in the HFE gene. Routine testing for two such mutations (H63D and S65C) using real-time genotyping deserves special care, as these mutations are in close proximity (6 bp) of each other. METHODS: A novel assay was designed for these two mutations based on a SimpleProbe assay format that allows for more flexibility in assay design, as it requires only one detection probe instead of the two probes that are commonly used with a hybridization probe based assay. RESULTS: The SimpleProbe assay format yielded data that were easily interpreted without significant optimizing efforts. CONCLUSIONS: The SimpleProbe assay format offers some unique advantages compared to hybridization probes and offers a robust and interesting alternative to hybridization probes in the detection of genetic variations. This is the first time that the use of this assay format is described in the clinical literature.