Detection of circulating tumor DNAs (ctDNAs) in cancer patients is an important component of cancer precision medicine ctDNAs. Compared to the traditional physical and biochemical methods, blood-based ctDNA detection offers a non-invasive and easily accessible way for cancer diagnosis, prognostic determination, and guidance for treatment. While studies on this topic are currently underway, clinical translation of ctDNA detection in various types of cancers has been attracting much attention, due to the great potential of ctDNA as blood-based biomarkers for early diagnosis and treatment of cancers. ctDNAs are detected and tracked primarily based on tumor-related genetic and epigenetic alterations. In this article, we reviewed the available studies on ctDNA detection and described the representative methods. We also discussed the current understanding of ctDNAs in cancer patients and their availability as potential biomarkers for clinical purposes. Considering the progress made and challenges involved in accurate detection of specific cell-free nucleic acids, ctDNAs hold promise to serve as biomarkers for cancer patients, and further validation is needed prior to their broad clinical use.

BackgroundVisceral leishmaniasis (VL) is still an important public health problem in China. In recent years endemic regions spread, prevalence increased, and even an outbreak of the disease occurred in China due to global warming and population movement. It is essential to elucidate the current epidemic situation and epidemiological characteristics of VL for designing control policy. In the present study we describe the current epidemiological profile and characteristics of VL in China based on retrospectively reviewing of VL cases reported between 2005 and 2010 by a passive surveillance system.MethodsThe present study was a retrospective review of VL cases notified between 2005 and 2010 based on the passive surveillance data. The data were tabulated, diagrammatized and analyzed through descriptive statistics in a Microsoft Excel spreadsheet.ResultsA total of 2450 VL cases were notified, with a mean of 408 cases per year. 61 counties were identified as endemic area with 2224 autochthonous cases, and the other 118 counties as non-endemic areas with 226 imported cases. 97.71% of cases were concentrated in Xinjiang, Gansu and Sichuan Provinces. 9 major counties reported a mean of > 10 cases per year, with a total of 1759 cases reported. Different types of VL revealed distinct epidemiological characteristics.ConclusionsThe number of VL cases and endemic counties both increased in the period 2005-2010 in China. Different type or sub-type of VL revealed distinct epidemiological characteristics. Therefore, differential control measures must be taken in different endemic areas against incidence increase and endemic area spread.

Precision medicine for cancer patients aims to adopt the most suitable treatment options during diagnosis and treatment of individuals. Detecting circulating tumor cell (CTC) or circulating tumor DNA (ctDNA) in plasma or serum could serve as liquid biopsy, which would be useful for numerous diagnostic applications. Liquid biopsies can help clinicians screen and detect cancer early, stratify patients to the most suitable treatment and real-time monitoring of treatment response and resistance mechanisms in the tumor, evaluate the risk for metastatic relapse, and estimate prognosis.We summarized the advantages and disadvantages of tissue and liquid biopsies.We also further compared and analyzed the advantages and limitations of detecting CTCs, ctDNAs, and exosomes. Furthermore, we reviewed the literature related with the application of serum or plasma CTCs, ctDNAs, and exosomes for diagnosis and prognosis of cancer.We also analyzed their opportunities and challenges as future biomarkers. In the future, liquid biopsies could be used to guide cancer treatment. They could also provide the ideal scheme to personalize treatment in precision medicine.