RESUMEN
Circulating tumor DNA (ctDNA) comes from tumor, reflecting the genetic information of the tumor well, and will change with the progress of tumor. In recent years, the unique capabilities of ctDNA have attracted much attention and been widely studied. In this paper, based on the summary of the source, properties and sample processing of ctDNA, its detection technology and application in cancer diagnosis and treatment are reviewed. The roles and importance of ctDNA reference material in second-generation sequencing are described. The urgency of establishing uniform standards and specifications of ctDNA in various processes, such as samples collection, storage, quantitative testing and data analysis, has been pointed out.
RESUMEN
Chitosan oligosaccharide(COS)is the N-acetyl-D-glucosamine and D-glucosamine oligomer linked to β(1→4)glycoside bond, which is an amino oligosaccharide with positive charge. GOS can be prepared via the deacetylation and hydrolysis of chitin from the exoskeleton of arthropod and insect and the cell wall of fungi. GOS is soluble in water, not cytotoxic, easy to be absorbed through intestinal tract, and mainly excreted from urine. COS and its derivatives have been known to have a variety of biological activities, including the anti-inflammatory, immunomodulatory, neuroprotective and antioxidant activities. This paper reviews the research progress in the preparation method, pharmacokinetics, bioactivity and the safety of GOS in recent years, hoping to provide a reference for related future researches.