Taking a pragmatic approach with a view to complete
Taking a pragmatic approach with a view to complete the study and because chemotherapy regimens in NETs are not standardized, we do not impose a specific regimen in both arms. However, one regimen in each arm is recommended in order to reduce heterogeneity: the ALKY-based chemotherapy arm will receive capecitabine (750 mg/m2 twice daily for 14 days, days 1–14) and temozolomide (temozolomide, 200 mg/m2 once daily for 5 days, days 10–14), every 28 days , , alternatively LV5FU2-dacarbazine (for patients with expected difficulties with adherence to oral chemotherapy) or 5FU-streptozotocine (only approved in France for pancreatic NET, therefore only used in this study in this situation). The recommended regimen in Ox-based chemotherapy arm is GEMOX (gemcitabine 1000 mg/m2 followed by oxalipatlin 100 mg/m2 every 2 weeks);  alternatively FOLFOX or CAPOX. Doses and monitoring of chemotherapies will be administered in accordance to French recommendations . The duration of chemotherapy recommended is at least 3 months (assessment of the primary endpoint), but physicians are allowed to continue chemotherapy, and do so usually for 4–12 months , , , , , .
Conflicts of interests
Funding The study is funded by the French National Cancer Institute (PHRCK-16-0208).
Source of support
Introduction Defined as a chemical modification by which methyl groups are precisely added to some nucleobases via DNA methyltransferase (MTase), DNA methylation changes the characteristics of nucleotides, i.e., transcription silencing , and thus plays an important role in chromosome inactivation, gene editing and gene 5-Methyl-UTP [, , , ]. Abnormal DNA methylation has received increasing attention because it has a significant impact on some cancers, such as breast cancer [6,7], especially in initial and developing diseases . Thus, methods for the detection of MTase activity, such as electrochemical experiments [, , , , ], colorimetric assays , chemical-assisted fluorescence assays [, , , , ], immune-based experiments, nanoparticle assays [, , , ], DNAzyme-based assays [24,25], chemiluminescence assays , among others, are urgently needed. For example, Chen et al. reported a sandwich biosensor utilizing CNNS-based ECL to detect Dam MTase recently, which is highly sensitive to most biosensors . Another method based on the entropy-driven toehold-mediated hairpin displacement was developed to evaluate DNA methylation just in one step . In addition, various strategies have been developed to augment the sensitivity of these assays. Nucleic acid amplification [, , ], for instance, is an effective method that can be flexibly combined with strand displacement amplification (SDA) , rolling circle amplification (RCA) [32,33], and hybridization chain reaction (HCR) . However, the amplification methods have inevitably increased the complexity of the detection system; thus, further improving or developing other simple and sensitive methods is still a pressing concern. As a newly emerging technology, nanoparticles or nanoclusters templated by DNA have attracted research interest as these molecules have the advantages of simplifying synthesis, utilizing flexible mechanisms and powerful signals, and having low cost, as well as the ability to be templated by proteins or other materials [35,36]. Different from the use of traditional metal ions [, , , ] used to form nanoparticles , copper nanoparticles (CuNPs) are better than silver or gold nanoparticles because they have a much higher sensitivity, faster synthetic speed, larger MegaStokes shift and low to no toxicity due to the existence of copper in organisms. Wang et al. reported transcription factor biosensing using DNA-templated copper nanoparticles , and Saman Hosseinkhani et al. designed a method utilizing copper nanoclusters for the detection of microRNA-155 .