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The analysis of cfDNA has been applied as a liquid biopsy in several malignancies. However, its value in the diagnosis and prognosis of cholangiocarcinoma (CCA) have not been well defined. We aimed to investigate the diagnostic and prognostic values of cfDNA level and tumor-specific mutation in circulating DNA (ctDNA) in CCA. The plasma cfDNA levels from 62 CCA patients, 33 benign biliary disease (BBD) patients and 30 normal controls were quantified by fluorescent assay. Targeted probe-based sequencing of 60 genes was applied for mutation profiling in 10 ctDNA samples and their corresponding treatment-naïve tissues. cfDNA levels in CCA were significantly higher than those in BBD and normal controls. We found that cfDNA levels at 0.2175 and 0.3388 ng/µL significantly discriminated CCA from healthy controls and BBD with 88.7 and 82.3% sensitivity and 96.7 and 57.6% specificity, respectively. cfDNA levels showed superior diagnostic efficacy in detecting CCA compared to CEA and CA19-9. ARID1A (30%), PBRM1 (30%), MTOR (30%), and FGFR3 (30%) mutations were the most common. Using nine frequently mutated genes in the ctDNA samples, the diagnostic accuracy of cfDNA sequencing was 90.8%, with 96.7% average sensitivity and 72.4% specificity. This study supports the use of cfDNA as a diagnosis and prognostic biomarker for CCA.

Objective The 3.7 kb deletion (-α 3.7 ) is the most common form of α + -thalassemia found in multiple populations which can be classified into three subtypes. In order not to mis-identify it, the molecular information within each population is required. We have addressed this in northeast Thai and Laos populations. Methods Screening for α + -thalassemia was initially done on 1192 adult Thai subjects. In addition, 77 chromosomes of Thai newborns and 26 chromosomes of Laos with -α 3.7 α + -thalassemia were also examined. All subjects were screened for -α 3.7 α + -thalassemia and subtyped by PCR-RFLP assay. Exact deletion breakpoint of each -α 3.7 subtype was determined by DNA sequencing. α-Globin gene haplotypes were determined. Results The proportions of -α 3.7 subtypes found in 216 Thai -α 3.7 chromosomes were 94.9% for -α 3.7I , 4.2% for α 3.7II and 0.9% for -α 3.7III . All 26 Laos -α 3.7 chromosomes were of -α 3.7I variety. At least six α-globin gene haplotypes were associated with the -α 3.7I α + -thalassemia. Conclusion All -α 3.7 subtypes were observed among Southeast Asian population. Haplotype analysis indicated a multiple origin of this common disorder in the region. A multiplex PCR assay has been developed for simultaneous detection of all subtypes of -α 3.7 α + -thalassemia as well as other α + -thalassemia found in the region including -α 4.2 α + -thalassemia, Hb Constant Spring and Hb Pakse.