Multi-marker analysis qPCR Colorectal cancer A B S T R A C TDevelopment of a Q-PCR-based assay for the high-performance analysis of circulating cellfree DNA (ccfDNA) requires good knowledge of its structure and size.In this work, we present the first visual determination of ccfDNA by Atomic Force Microscopy (AFM) on plasma samples from colorectal cancer (CRC) patients and healthy donors.In addition to the examination of fragment size distribution profile as performed by Q-PCR, this analysis confirms that ccfDNA is highly fragmented and that more than 80% of ccfDNA fragments in CRC plasma are below 145 bp. We adapted an Allele-Specific Blocker (ASB) Q-PCR to small ccfDNA fragments to determine simultaneously the total ccfDNA concentration, the presence of point mutation, the proportion of mutated allele, and a ccfDNA integrity index. The data validated analytically these four parameters in 124 CRC clinical samples and 71 healthy individuals. The multi-marker method, termed Intplex, enables sensitive and specific non-invasive analysis of tumor ccfDNA, which has great potential in terms of cost, quality control, and easy implementation in every clinical center laboratory.ª 2014 Federation of European Biochemical Societies.Published by Elsevier B.V. All rights reserved. IntroductionCirculating cell-free DNA (ccfDNA) is an emerging biomarker in cancer diagnosis and theragnosis (Schwarzenbach et al., 2011). The use of ccfDNA presents conceptual advantages compared to classic genetic analysis via tumor-tissue sampling. CcfDNA analysis is non-invasive and enables day-to-day patient follow-up (Diehl et al., 2008a, b;Dawson et al., 2013) and monitoring of treatment response (Gorges et al., 2012). CcfDNA also exhibits the genetic and the epigenetic alterations from its tumor of origin (Stroun et al., 2001). Analysis of these alterations could provide valuable information to tailor the clinician's choice of treatment given the restrictions of the new targeted therapies: KRAS mutation status has been found to be predictive of response to cetuximab, an anti-EGFR (epidermal growth factor receptor) monoclonal antibody (mAb) in colorectal cancer (CRC) (Li evre et al., 2006) and patients with metastatic colorectal cancer (mCRC) bearing KRAS mutations do not respond to cetuximab and panitumumab anti-EGFR mAbs, either as single agent or in combination with chemotherapy (Van Cutsem et al., 2011;Amado et al., 2008). In CRC, the KRAS oncogene is often mutated (w35% of cases, Cosmic Sanger Analysis (Bamford et al., 2004)). Although the V600E BRAF mutation is observed less frequently in CRC patients (5e12%, Cosmic Sanger (Bamford et al., 2004)), it a strong indicator of poor prognosis (Di Nicolantonio et al., 2008a

IMRT-data-driven VMAT planning offers a potential method for generating VMAT plans that are comparable to IMRT plans in terms of dosimetric quality.

No abstract

No abstract

Using atomic force microscopy (AFM), we have investigated neutron-induced DNA double-strand breaks in plasmids in aqueous solution. AFM permits direct measurement of individual DNA molecules with an accuracy of a few nanometers. Furthermore, the analysis of the DNA fragment size distribution is non-parametric, whereas other methods are dependent on the model. Neutron irradiation of DNA results in the generation of many short fragments, an observation not made for damage induced by low-LET radiation. These data provide clear experimental evidence for the existence of clustered DNA double-strand breaks and demonstrate that short DNA fragments may be produced by such radiations in the absence of a nucleosomal DNA structure.