Methylation of DNA Repair Genes as a Prognostic Biomarker in AML of a TCGA-LAML Cohort.

BACKGROUND: Dysregulation of DNA damage response and altered DNA methylation in acute myeloid leukemia (AML) have been reported, but the impact of methylation of DNA repair genes has not yet been researched. We aimed to predict the prognosis of non-APL AML patients based on the known CpG site methylation levels of DNA repair genes through The Cancer Genome Atlas AML project (TCGA-LAML). METHODS: We utilized TCGA-LAML cohort (174 non-APL AML) for the methylation data of 22 DNA repair genes. RESULTS: In univariate analysis among 174 non-APL AML patients of the TCGA-LAML cohort, the hypermethylation of MLH1, RAD51, and ATM showed superior overall survival (OS) than non-hypermethylated groups, while hypermethylation of RAD23A, RAD23B, MLH1, MSH2, BRCA1, BRCA2, RAD50, and PARP1 was associated with poor OS. We demonstrated that CpG hypermethylation levels of DNA repair genes differed according to the AML cytogenetic risk groups. In multivariate analysis, hypermethylation of MLH1 and RAD51 showed better OS than non-hypermethylated patients, but hypermethylation of MSH2 and RAD50 showed worse OS than non-hypermethylated patients. CONCLUSION: Methylation of 4 DNA repair genes, such as MLH1, RAD51, MSH2, and RAD50, have the potential to be independent risk factors in non-APL AML patients.

Analytical Performance Evaluation of Goldstream Fungus (1-3)-ß-D Glucan.

BACKGROUND: (1-3)-ß-D-glucan (BDG) is a fast and simple assay to diagnose invasive fungal infection. In this study, we evaluated the performance of the Goldstream BDG assay (Beijing Gold Mountainriver Tech Development) performed on the automated analyzer, IGL-200 (Genobio Pharmaceutical). METHODS: The precision and linearity of the Goldstream BDG assay were evaluated according to Clinical and Laboratory Standards Institute procedures. BDG results performed on the IGL-200 were compared to a manual photometer, MB-80A (Genobio Pharmaceutical). The manufacturer-provided reference interval was verified. RESULTS: Within-laboratory imprecision (% Coefficient of Variation) was 9.4%. The best polynomial fit was third-order within the manufacturer's claimed linear range (32.0 - 830.0 pg/mL). The BDG assay performed on IGL-200 and MB-80A showed a total agreement of 97.6%. All healthy subjects were within range of the manufacture provided reference interval. CONCLUSIONS: The analytical performance of the Goldstream BDG assay was clinically acceptable.

Differentiation of cancer cell origin and molecular subtype by plasma membrane N-glycan profiling.

In clinical settings, biopsies are routinely used to determine cancer type and grade based on tumor cell morphology, as determined via histochemical or immunohistochemical staining. Unfortunately, in a significant number of cases, traditional biopsy results are either inconclusive or do not provide full subtype differentiation, possibly leading to inefficient or ineffective treatment. Glycomic profiling of the cell membrane offers an alternate route toward cancer diagnosis. In this study, isomer-sensitive nano-LC/MS was used to directly obtain detailed profiles of the different N-glycan structures present on cancer cell membranes. Membrane N-glycans were extracted from cells representing various subtypes of breast, lung, cervical, ovarian, and lymphatic cancer. Chip-based porous graphitized carbon nano-LC/MS was used to separate, identify, and quantify the native N-glycans. Structure-sensitive N-glycan profiling identified hundreds of glycan peaks per cell line, including multiple isomers for most compositions. Hierarchical clusterings based on Pearson correlation coefficients were used to quickly compare and separate each cell line according to originating organ and disease subtype. Based simply on the relative abundances of broad glycan classes (e.g., high mannose, complex/hybrid fucosylated, complex/hybrid sialylated, etc.), most cell lines were readily differentiated. More closely related cell lines were differentiated based on several-fold differences in the abundances of individual glycans. Based on characteristic N-glycan profiles, primary cancer origins and molecular subtypes could be distinguished. These results demonstrate that stark differences in cancer cell membrane glycosylation can be exploited to create an MS-based biopsy, with potential applications toward cancer diagnosis and direction of treatment.

Integration of an MC-80 Digital Image Analyzer With an Automated BC-6800Plus Hematology Analyzer Enables Accurate Platelet Counting in Samples With EDTA-Induced Pseudothrombocytopenia.

Background: EDTA-induced pseudothrombocytopenia (PTCP) during whole blood collection requires significant laboratory resources to obtain accurate results. We evaluated platelet-deaggregation function in EDTA-induced PTCP and platelet-clump flagging by the BC-6800Plus hematology analyzer using integrated digital image analysis. Methods: We prospectively collected 132 whole blood samples suspected of platelet clumping (102 in EDTA and 30 in sodium citrate) from 88 individuals. We compared platelet counts determined using the platelet count by impedance (PLT-I) function of the DxH 900 hematology analyzer and the PLT-I or optical platelet count (PLT-O) function of the BC-6800Plus. Platelet clumping was verified through manual inspection and the MC-80 digital image analyzer. Results: Among the 132 whole blood samples, 43 EDTA samples showed platelet clumping. The DxH 900 PLT-I and BC-6800Plus PLT-I results demonstrated a strong correlation (r=0.711) for the EDTA samples but only a moderate correlation with the BC-6800Plus PLT-O results (r=0.506 and 0.545, respectively). The BC-6800Plus PLT-O results were consistent with the sodium citrate platelet counts, with a median dissociation rate of 102.5% (range, 74.9%-123.1%). The DxH 900 and BC-6800Plus analyzers had sensitivity values of 0.79 and 0.72, respectively, for platelet-clump flagging. When integrating the MC-80 digital image analysis results, the sensitivity of BC-6800Plus improved to 0.89 (standard mode) or 1.0 (PLT-Pro mode). Conclusions: BC-6800Plus PLT-O measurement results are close to the actual values obtained by platelet deaggregation with PTCP samples. Integrating the BC-6800Plus with a digital imaging analyzer effectively improved the diagnosis of PTCP and reduced the requirement for additional laboratory procedures.

Multidrug-Resistant and Carbapenemase Gene-Carrying Acinetobacter colistiniresistens Isolated from Bloodstream Infection.

In this study, we investigated the antimicrobial susceptibility and molecular characteristics of antimicrobial resistance of Acinetobacter colistiniresistens strains isolated from the bloodstream using whole-genome sequencing. Clinical isolates identified as Acinetobacter baumannii and showing colistin resistance at the time of detection were collected. Antimicrobial susceptibility was determined using the VITEK2 system (bioMérieux) and Sensititre system (Thermo Fisher Scientific). Species identification and antimicrobial resistance gene searches were performed through whole-genome sequencing. Through whole-genome sequencing, three colistin-resistant strains from the bloodstream were identified as A. colistiniresistens. All three A. colistiniresistens strains were resistant to two or more antimicrobial agents except for colistin, and two of them were resistant to carbapenems. Genes involved in aminoglycoside [AAC(3)-Ⅱb, AAC(6')-Ⅰj, aadA2, ANT(3″)-Ⅱb, APH(3')-Ⅵa], macrolide (mphD, msrE), carbapenem and cephalosporin (OXA-420, VIM-2), fluoroquinolone and tetracycline (adeF), and sulfonamide (sul1, sul2) resistance were detected. We report multidrug-resistant A. colistiniresistens strains isolated from the bloodstream through whole-genome sequencing. Two strains carried carbapenemase genes, and this is the first report of VIM-2-producing A. colistiniresistens.

Large-Scale Clinical Evaluation of Rapid Blood Culture Identification Panels for Bloodstream Infections at a Tertiary Hospital.

The prompt implementation of optimal antibacterial therapy through the rapid identification of the causative organisms is essential for improving outcomes for critically ill patients with bloodstream infections. We evaluated the clinical performance of the FilmArray blood culture identification (BCID) panel for rapidly identifying causative pathogens in the bloodstream using large-scale clinical samples. We analyzed the results of identification using a BCID panel performed on 2005 positive blood culture bottles from September 2019 to June 2022. Pathogen detection efficiency and interval from Gram staining to identification using the BCID panel were compared to those of conventional identification systems-VITEK MS MALDI-TOF Mass Spectrometer and Vitek2-and antibiotic susceptibility testing-Vitek2. We detected 2167 isolates from 2005 positive blood culture bottles. In these isolates, the BCID panel showed 93% full agreement-both organisms and antimicrobial resistance genes were matched, and no off-target organisms were detected. Species-level discordance was found in 0.6% of tests. Sixty-five isolates (3.0%) were only detected by BCID, whereas 22 isolates (1.0%) from the on-target panel were not detected by BCID. This large-scale study demonstrated that the BCID panel was a reliable and rapid identification method for directly identifying bloodstream pathogens in a positive blood culture.

The Impact of the Rapid Blood Culture Identification Panel on Antibiotic Treatment and Clinical Outcomes in Bloodstream Infections, Particularly Those Associated with Multidrug-Resistant Micro-Organisms.

We evaluated the impact of the FilmArray blood culture identification (BCID) panel on the time taken to administer effective antibiotics and the clinical outcomes of bloodstream infections. We retrospectively screened patients with bloodstream infections who underwent BCID testing and compared them to a historical control group that received conventional culture testing. A total of 144 and 214 patients who underwent BCID and conventional cultures, respectively, were compared. The 30-day mortality (BCID: 9.7% vs. conventional method: 10.7%, p = 0.755), time to effective antibiotic administration (3 h for both BCID and conventional method, p = 0.789), and time to appropriate antibiotic administration did not differ significantly between the groups. BCID was not significantly associated with 30-day mortality after adjusting for the Pitt bacteremia score and the Charlson comorbidity index (adjusted OR = 0.833, CI; 0.398-1.743). Compared with conventional methods, BCID reduced the time to administration of effective antibiotics in cases of carbapenem-resistant Enterobacterales (CRE) (39 h vs. 93 h, p = 0.012) and vancomycin-resistant enterococci (VRE) (50 h vs. 92 h, p < 0.001) bacteremia. BCID did not affect the clinical outcomes of overall bloodstream infections; however, it contributed to the early administration of effective antibiotics in cases of CRE and VRE bacteremia.

Germline pathogenic variants in unselected Korean men with prostate cancer.

PURPOSE: Prostate cancer is one of the most heritable cancers and prostate cancer with germline mutations is associated with aggressive features and a poor prognosis. We investigated germline variants in unselected Korean men with prostate cancer. MATERIALS AND METHODS: In this study, we prospectively collected buccal swab DNA from 120 unselected Korean men with prostate cancer, and performed massively parallel sequencing. Identified germline variants were interpreted according to the American College of Medical Genetics and Genomics/Association for Molecular Pathology 2015 guidelines. RESULTS: Of the 120 patients, 30 had regional or metastatic disease and 10, 34, 25, and 21 patients were categorized as having low, intermediate, high, or very high-risk disease, respectively. Of the 88 germline variants, 6 pathologic or likely pathogenic variants were identified in 7 patients (5.8%) with BRCA2 (1.7%), HOXB13 (1.7%), PALB2 (0.8%), ATM (0.8%), and MSH2 (0.8%). Of 7 patients, 2 possessed intermediate risk disease that was not included in the recommendation for genetic testing. We identified the Gly132Glu variant, which was different from the Gly84Glu variant of the HOXB13 gene in Western populations. CONCLUSIONS: This study presents the first analysis of germline variants in unselected Korean men with prostate cancer. Our results showed comparable germline prevalence with previous studies and provides evidence for the necessity of genetic testing in Korean men with prostate cancer.

How Significant Are Xpert Xpress SARS-CoV-2 Test Findings When Only an N2 Gene Is Detected?

The rapid identification of patients infected with COVID-19 during the SARS-CoV-2 pandemic is critical to operating emergency rooms effectively. Xpert Xpress SARS-CoV-2 (Xpert) assays are increasingly being used in the rapid screening of COVID-19. We evaluated the clinical performance of Xpert by comparing findings with those of qRT-PCR evaluations and included the clinical features of patients visiting the emergency department. Positive results with Xpert testing (n = 370) were compared with qRT-PCR findings, demonstrating a 91.9% intertest agreement. We reviewed the subsequent COVID-19 test results and SARS-CoV-2 infection histories for individuals showing discrepancies in Xpert and qRT-PCR testing and determined whether the findings were true-positive or false-positive. The true-positive rate for Xpert testing was 95.4% (353/370); the remaining 17 samples (4.6%) were false-positive. All false-positive data for Xpert testing showed N2 signals amplified to Ct values of ≥40 with no E gene signals. Rapid Xpert testing is highly sensitive and shows a good performance overall in challenging situations, such as an emergency room. However, we considered the possibility of false-positive Xpert results given an N2 gene signal only, especially given high Ct values. We recommend interpreting test data with caution and considering retesting over time.

Variant Prediction by Analyzing RdRp/S Gene Double or Low Amplification Pattern in Allplex SARS-CoV-2 Assay.

The spread of delta variants (B.1.671.2) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a severe global threat. Multiplex real-time PCR is a common method for confirming SARS-CoV-2 infection, however, additional tests, such as whole genomic sequencing, are required to reveal the presence or type of viral mutation. Moreover, applying whole genomic sequencing to all SARS-CoV-2 positive samples is challenging due to time and cost constraints. Here, we report that the double or low amplification curve observed during RNA-dependent RNA polymerase (RdRp) gene/S gene amplification in the Allplex SARS-CoV-2 Assay is related to delta/alpha variants. We analyzed the RdRp/S gene amplification curve using 94 samples confirmed as SARS-CoV-2 infection by the Allplex SARS-CoV-2 Assay from January to August, 2021. These positive samples identified variant types using the Novaplex SARS-CoV-2 Variants I and IV Assays. Overall, 17 samples showing a double curve and 11 samples showing a low amplification pattern were associated with alpha-/delta-type strains with variants in the P681 region. The double or low curve shown in the RdRp gene amplification curve had 100% sensitivity and 100% specificity for diagnosing delta/alpha variants. During the SARS-CoV-2 virus diagnostic RT-PCR test using the Allplex SARS-CoV-2 Assay, we could consider the presence of delta/alpha variants in the samples with double or low amplification curve of the RdRp/S gene channel. This PCR amplification curve abnormality enables rapid and cost-effective variant type prediction during SARS-CoV-2 diagnostic testing in clinical laboratories.

Coexistence of Primary Myelofibrosis and Paroxysmal Nocturnal Hemoglobinuria Clone with JAK2 V617F, U2AF1 and SETBP1 Mutations: A Case Report and Brief Review of Literature.

Primary myelofibrosis (PMF) and paroxysmal nocturnal hemoglobinuria (PNH) are very rare diseases, respectively, and it is uncommon to have both diseases together. Mutational profiling using next-generation sequencing in PMF and PNH detected additional mutations associated with myeloid neoplasms, suggesting a step-wise clonal evolution. We present here a very rare case with PMF and PNH with JAK2 V617F, U2AF1 and SETBP1 mutations at the time of diagnosis. The combination of these two diseases and three genetic mutations is difficult to interpret at once. (i.e., the sequence of these two clonal diseases or the time points of acquiring these mutations). Our report suggests that when diagnosing or treating patients with PMF, it is necessary to keep in mind that PNH may be present at the same time or sometimes new. The genetic mutations simultaneously found in this patient require further research to elucidate the clinical significance and their genetic associations fully.

Analytical Validation of a Pan-Cancer Panel for Cell-Free Assay for the Detection of EGFR Mutations.

Liquid biopsies have increasingly shown clinical utility. Although next-generation sequencing has been widely used for the detection of somatic mutations from plasma, performance characteristics vary by platform. Therefore, thorough validation is mandatory for clinical use. This study aimed to evaluate the analytical validity of the Oncomine Pan-Cancer Cell-Free Assay. A massively parallel sequencing for the assay was performed using the Ion S5 XL System with Ion 540 kit. The analytical sensitivity and precision were evaluated using pre-characterized reference materials. The specificity was evaluated using plasma from healthy subjects. A comparison with the Cobas EGFR Mutation Test v2 was performed using reference materials and plasma from lung cancer patients. For SNVs and short indels, the analytical sensitivities at variant allele frequencies (VAFs) of 0.1%, 0.5%, and 1% were 50%, 93.4%, and 100% with 20 ng of input, respectively. The overall precision of the true positive variants was 98% at a VAF of 1% with 20 ng input. The assay showed a similar sensitivity to that of the Cobas EGFR Mutation Test v2 at a VAF of 0.5% with 20 ng of input and 100% concordance on clinical samples. The Pan-Cancer Cell-Free Assay can be applied to detect EGFR mutations in advanced lung cancer patients, although follow-up studies will be needed to evaluate the analytical validity for other types of genes and aberrations using clinical samples.

Genetic Characteristics and Phenotype of Korean Patients with Stickler Syndrome: A Korean Multicenter Analysis Report No. 1.

Stickler syndrome is an inherited connective tissue disorder of collagen. There are relatively few reports of East Asian patients, and no large-scale studies have been conducted in Korean patients yet. In this study, we retrospectively analyzed the genetic characteristics and clinical features of Korean Stickler syndrome patients. Among 37 genetically confirmed Stickler syndrome patients, 21 types of gene variants were identified, of which 12 were novel variants. A total of 30 people had variants in the COL2A1 gene and 7 had variants in the COL11A1 gene. Among the types of pathogenic variants, missense variants were found in 11, nonsense variants in 8, and splice site variants in 7. Splicing variants were frequently associated with retinal detachment (71%) followed by missense variants. This is the first large-scale study of Koreans with Stickler syndrome, which will expand the spectrum of genetic variations of Stickler syndrome.

Self-illuminating quantum dot conjugates for in vivo imaging.

Fluorescent semiconductor quantum dots hold great potential for molecular imaging in vivo. However, the utility of existing quantum dots for in vivo imaging is limited because they require excitation from external illumination sources to fluoresce, which results in a strong autofluorescence background and a paucity of excitation light at nonsuperficial locations. Here we present quantum dot conjugates that luminesce by bioluminescence resonance energy transfer in the absence of external excitation. The conjugates are prepared by coupling carboxylate-presenting quantum dots to a mutant of the bioluminescent protein Renilla reniformis luciferase. We show that the conjugates emit long-wavelength (from red to near-infrared) bioluminescent light in cells and in animals, even in deep tissues, and are suitable for multiplexed in vivo imaging. Compared with existing quantum dots, self-illuminating quantum dot conjugates have greatly enhanced sensitivity in small animal imaging, with an in vivo signal-to-background ratio of > 10(3) for 5 pmol of conjugate.

Reinterpretation of BRCA1 and BRCA2 variants of uncertain significance in patients with hereditary breast/ovarian cancer using the ACMG/AMP 2015 guidelines.

BACKGROUND: Although BRCA1 or BRCA2 (BRCA1/2) genetic testing plays an important role in determining treatment modalities in patients with hereditary breast and ovarian cancer, sequence variants with unknown clinical significance or variant of uncertain significance (VUS) have limited use in medical decision-making. With vast quantities of gene-related data being updated, the clinical significance of VUS may change over time. We reinterpreted the sequence variant previously reported as BRCA1/2 VUS results in patients with breast or ovarian cancer and assessed whether the clinical significance of VUS was changed. METHODS: We retrospectively reviewed medical records of 423 breast or ovarian cancer patients who underwent BRCA1/2 genetic testing from 2010 to 2017. The VUSs in BRCA1/2 were reanalyzed using the 2015 American College of Medical Genetics and Genomics and the Association for Molecular Pathology standards and guidelines (ACMG/AMP 2015 guidelines) and the VUS was reclassified into five categories: "pathogenic", "likely pathogenic", "VUS", "likely benign", and "benign". RESULTS: A total of 75 patients (48 sequence types of VUS) were identified as carrying either one or more VUS in BRCA1/2. Among the 75 patients, two patients (2.7%) were reclassified as "likely pathogenic", 30 patients (40.0%) were reclassified as either "benign" or "likely benign", and the remaining 43 patients (57.3%) were still classified as VUS category. CONCLUSIONS: Since the clinical significance of VUS in BRCA1/2 may vary from time to time, reinterpretation of the VUS results could contribute to clinical decision-making.

Multiplex detection of protease activity with quantum dot nanosensors prepared by intein-mediated specific bioconjugation.

We report here a protease sensing nanoplatform based on semiconductor nanocrystals or quantum dots (QDs) and bioluminescence resonance energy transfer (QD-BRET) to detect the protease activity in complex biological samples. These nanosensors consist of bioluminescent proteins as the BRET donor, quantum dots as the BRET acceptor, and protease substrates sandwiched between the two as a sensing group. An intein-mediated conjugation strategy was developed for site-specific conjugation of proteins to QDs in preparing these QD nanosensors. In this traceless ligation, the intein itself is spliced out and excluded from the final conjugation product. With this method, we have synthesized a series of QD nanosensors for highly sensitive detection of an important class of protease matrix metalloproteinase (MMP) activity. We demonstrated that these nanosensors can detect the MMP activity in buffers and in mouse serum with the sensitivity to a few nanograms per milliliter and secreted proteases by tumor cells. The suitability of these nanosensors for a multiplex protease assay has also been shown.

HaloTag protein-mediated specific labeling of living cells with quantum dots.

Quantum dots emerge as an attractive alternative to small molecule fluorophores as fluorescent tags for in vivo cell labeling and imaging. This communication presents a method for specific labeling of live cells using quantum dots. The labeling is mediated by HaloTag protein expressed at the cell surface which forms a stable covalent adduct with its ligand (HaloTag ligand). The labeling can be performed in one single step with quantum dot conjugates that are functionalized with HaloTag ligand, or in two steps with biotinylated HaloTag ligand first and followed by streptavidin coated quantum dots. Live cell fluorescence imaging indicates that the labeling is specific and takes place at the cell surface. This HaloTag protein-mediated cell labeling method should facilitate the application of quantum dots for live cell imaging.

Improved QD-BRET conjugates for detection and imaging.

Self-illuminating quantum dots, also known as QD-BRET conjugates, are a new class of quantum dot bioconjugates which do not need external light for excitation. Instead, light emission relies on the bioluminescence resonance energy transfer from the attached Renilla luciferase enzyme, which emits light upon the oxidation of its substrate. QD-BRET combines the advantages of the QDs (such as superior brightness and photostability, tunable emission, multiplexing) as well as the high sensitivity of bioluminescence imaging, thus holding the promise for improved deep tissue in vivo imaging. Although studies have demonstrated the superior sensitivity and deep tissue imaging potential, the stability of the QD-BRET conjugates in biological environment needs to be improved for long-term imaging studies such as in vivo cell tracking. In this study, we seek to improve the stability of QD-BRET probes through polymeric encapsulation with a polyacrylamide gel. Results show that encapsulation caused some activity loss, but significantly improved both the in vitro serum stability and in vivo stability when subcutaneously injected into the animal. Stable QD-BRET probes should further facilitate their applications for both in vitro testing as well as in vivo cell tracking studies.

Imaging target mRNA and siRNA-mediated gene silencing in vivo with ribozyme-based reporters.

Noninvasive imaging of specific mRNAs in living subjects promises numerous biological and medical applications. Common strategies use fluorescently or radioactively labelled antisense probes to detect target mRNAs through a hybridization mechanism, but have met with limited success in living animals. Here we present a novel molecular imaging approach based on the group I intron of Tetrahymena thermophila for imaging mRNA molecules in vivo. Engineered trans-splicing ribozyme reporters contain three domains, each of which is designed for targeting, splicing, and reporting. They can transduce the target mRNA into a reporter mRNA, leading to the production of reporter enzymes that can be noninvasively imaged in vivo. We have demonstrated this ribozyme-mediated RNA imaging method for imaging a mutant p53 mRNA both in single cells and noninvasively in living mice. After optimization, the ribozyme reporter increases contrast for the transiently expressed target by 180-fold, and by ten-fold for the stably expressed target. siRNA-mediated specific gene silencing of p53 expression has been successfully imaged in real time in vivo. This new ribozyme-based RNA reporter system should open up new avenues for in vivo RNA imaging and direct imaging of siRNA inhibition.

F-18 fluorodeoxyglucose positron emission tomography for differential diagnosis and prognosis prediction of vascular tumors.

The spectrum of vascular tumors ranges from hemangioma (HEM), to epithelioid hemangioendothelioma (EHE) and to angiosarcoma (AS). To the best of our knowledge, the usefulness of F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) for vascular tumors has never been comprehensively studied. The present study investigated the usefulness of FDG-PET for pathologically diagnosed vascular tumors. The present study included 26 patients with vascular tumor (male:female, 17:9; age, 60.9±14.4 years; 7 HEM, 6 EHE and 13 AS) who underwent FDG-PET between January 2007 and May 2014 at the Seoul National University Bundang Hospital (Seongnam, Korea) and Konkuk University Medical Center, (Seoul, Korea). Representative FDG uptake was measured as the maximum standardized uptake value (SUVmax) over the lesion with the highest FDG uptake. Disease progression was clinically defined as the aggravation of known lesions or novel lesion development during follow-up on computed tomography, magnetic resonance imaging, or FDG-PET. FDG-PET revealed multi-organ involvement only in AS (6/13 [46.2%]), whereas HEM and EHE involved a single organ. Tumor SUVmax was significantly greater in AS (6.32±4.84) compared with EHE (3.10±2.68) and HEM (2.33±0.76) (P=0.0284). There was no difference in tumor SUVmax between HEM and EHE (P>0.05). Disease progression was primarily noticed in AS (9/13 [69.2%]). Only 1 patient with EHE (1/6=16.7%) and no patients with HEM (0/7=0%) experienced disease progression. Mortality was reported only in patients with AS (4/13 [30.8%]). Using the cutoff SUVmax of 3.0, the two-year progression-free survival rate of 14 patients with tumor SUVmax <3.0 (75.0%) was significantly higher compared with that of 12 patients with tumor SUVmax ≥3.0 (0%) (P=0.0053). In conclusion, FDG-PET is useful for the differential diagnosis and prognosis prediction of vascular tumors.