Myeloproliferative neoplasms (MPNs) are clonal hematopoietic stem cell disorders characterized by the proliferation of one or more myeloid lineages. The current study demonstrates that three driver mutations were detected in 82.6% of 407 MPNs with a mutation distribution of JAK2 in 275 (67.6%), CALR in 55 (13.5%) and MPL in 6 (1.5%). The mutations were mutually exclusive in principle except in one patient with both CALR and MPL mutations. The driver mutation directed the pathologic features of MPNs, including lineage hyperplasia, laboratory findings and clinical presentation. JAK2-mutated MPN showed erythroid, granulocytic and/or megakaryocytic hyperplasia whereas CALR- and MPL-mutated MPNs displayed granulocytic and/or megakaryocytic hyperplasia. The lineage hyperplasia was closely associated with a higher mutant allele burden and peripheral cytosis. These findings corroborated that the lineage hyperplasia consisted of clonal proliferation of each hematopoietic lineage acquiring driver mutations. Our study has also demonstrated that bone marrow (BM) fibrosis was associated with disease progression. Patients with overt fibrosis (grade ⩾2) presented an increased mutant allele burden (P<0.001), an increase in chromosomal abnormalities (P<0.001) and a poor prognosis (P<0.001). Moreover, among patients with overt fibrosis, all patients with wild-type JAK2/CALR/MPL (triple-negative) showed genomic alterations by genome-wide microarray study and revealed the poorest overall survival, followed by JAK2-mutated MPNs. The genetic–pathologic characteristics provided the information for understanding disease pathogenesis and the progression of MPNs. The prognostic significance of the driver mutation and BM fibrosis suggests the necessity of a prospective therapeutic strategy to improve the clinical outcome.

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Summary Pseudozyma species rarely cause invasive diseases in humans, which are usually isolated from plants. There have been anecdotal reports regarding Pseudozyma species infections in patients with underlying diseases or in neonates. However, clinical data and the pathogenicity in humans are still insufficient. We experienced a case of Pseudozyma aphidis fungaemia with invasive fungal pneumonia that developed during reinduction chemotherapy in a 51‐year‐old male with acute myeloid leukaemia (AML). P. aphidis was suspected based on the morphology of the yeast isolated from the blood and was confirmed via rDNA gene sequencing analysis. The patient successfully underwent stem cell transplantation with continuing antifungal treatment and finally completely recovered from both the AML and infectious complications. Here, we report a case of P. aphidis infection that developed during neutropenia in an AML patient and review the global literature.

BackgroundWhile the majority of germline inactivating mutations in BRCA1/2 are small-scale mutations, large genomic rearrangements (LGRs) are also detected in a variable proportion of patients. However, routine genetic methods are incapable of detecting LGRs, and comprehensive genetic testing algorithm is necessary.MethodsWe performed multiplex ligation-dependent probe amplification assay for small-scale mutation negative patients at high-risk for LGR, based on previously published LGR risk criteria. The inclusion criteria for the high-risk subgroup were personal history of 1) early-onset breast cancer (diagnosed at ≤36 years); 2) two breast primaries; 3) breast cancer diagnosed at any age, with ≥1 close blood relatives (includes first-, second-, or third-degree) with breast and/or epithelial ovarian cancer; 4) both breast and epithelial ovarian cancer diagnosed at any age; and 5) epithelial ovarian cancer with ≥1 close blood relatives with breast and/or epithelial ovarian cancer.ResultsTwo LGRs were identified. One was a heterozygous deletion of exon 19 and the other was a heterozygous duplication of exon 4–6. The prevalence of LGRs was 7% among Sanger-negative, high-risk patients, and accounted for 13% of all BRCA1 mutations and 2% of all patients. Moreover, LGRs reported in Korean patients, including our 2 newly identified cases, were found exclusively in families with at least one high-risk feature.ConclusionsOur result suggests that selective LGR screening for Sanger-negative, high-risk patients is necessary for Korean patients.

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Background Flow cytometry (FCM) is commonly used to identify many cell populations. We developed a white blood cell (WBC) differential counting system for detecting abnormal cells using FCM incorporating 10 colors and 11 antibodies in a single tube, called “10-color LeukoDiff,” and evaluated its performance. Methods Ninety-one EDTA-anti-coagulated peripheral blood samples from 76 patients were analyzed using 10-color LeukoDiff. We compared 10 color LeukoDiff results with the results of manual differential count (manual diff). WBCs were classified into 17 cell populations: neutrophils, total lymphocytes, T lymphocytes, B lymphocytes, CD5 and CD19 co-expressing lymphocytes, natural killer cells, total monocytes, 16+ monocytes, eosinophils, immature granulocytes, basophils, myeloblasts, B-blasts, T-blasts, myeloid antigen-positive B-blasts, CD19- plasma cells, and 19+ plasma cells. Results The correlations between the 10-color LeukoDiff and manual diff results were strong (r>0.9) for mature neutrophils, lymphocytes, eosinophils, immature granulocytes, and blasts and moderate for monocytes and basophils (r=0.86 and 0.74, respectively). There was no discrepancy in blast detection between 10-color LeukoDiff and manual diff results. Furthermore, 10-color LeukoDiff could differentiate the lineage of the blasts and separately count chronic lymphocytic leukemic cells and multiple myeloma cells. Conclusions The 10-color LeukoDiff provided an accurate and comprehensive WBC differential count. The most important ability of 10-color LeukoDiff is to detect blasts accurately. This system is clinically useful, especially for patients with hematologic diseases, such as acute leukemia, chronic lymphocytic leukemia, and multiple myeloma. Application of this system will improve the development of FCM gating strategy designs.

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Background: Three chromogenic media using direct inoculation were compared with enriched enterococcosel broth for vancomycin-resistant Enterococcus faecium and/or Enterococcus faecalis (VRE) surveillance. Methods: A total of 174 rectal swabs were included for VRE surveillance. The specimens were transferred in enterococcosel broth (EB). An aliquot of the broth was inoculated onto Brilliance VRE, chromID VRE, and VRESelect media and incubated for up to 48 h. We examined each media and EB after 24 h and 48 h of incubation. When appropriately colored colonies were observed, identification was confirmed using the VITEK-2 system and/or VITEK MS. Vancomycin susceptibility was confirmed by disk diffusion test. The presence of resistance genes was confirmed using Anyplex VanR Real-time Detection (Seegene, Korea