T-Cell Receptor Rearrangements Determined Using Fragment Analysis in Patients With T-Acute Lymphoblastic Leukemia.

BACKGROUND: Chromosomal abnormalities and common genetic rearrangements related to T-acute lymphoblastic leukemia (T-ALL) are not clear. We investigated T-cell receptor (TCR) rearrangement in Korean T-ALL patients by fragment analysis, examining frequency, association between clinicopathologic characteristics and TCR clonality, and feasibility for detecting minimal residual disease (MRD). METHODS: In 51 Korean patients diagnosed as having T-ALL, TCR rearrangement was analyzed using the IdentiClone TCR gene clonality assay (InVivoScribe Technologies, San Diego, CA, USA) from archived bone marrow specimens. Limit of detection (LOD) and clonal stability at relapse were evaluated. The association between clinical prognosis and TCR clonality was examind by age and immunophenotypic classification. RESULTS: Thirty-eight patients (74.5%) had 62 clonal products of TCRß, TCRγ, and/or TCRδ rearrangements at diagnosis. Children with T-ALL (<12 years) showed a higher frequency of clonality (93.8%) than adolescents/adults (65.7%; ≥12 years). Patients with a mature immunophenotype (84.4%) showed a relatively higher frequency of clonality than those with the immature immunophenotype (57.9%). Survival and event-free survival were not influenced by immunophenotype or TCR clonality. The LOD was 1%. Clonal evolution at the relapse period was noted. CONCLUSIONS: The overall detection rate of TCR clonality was 74.5%. Survival did not differ by TCR clonality or immunophenotype and age group. Fragment analysis of TCR rearrangement cannot be used to assess MRD due to low sensitivity. Further research on the relationship between prognosis and frequency of TCR rearrangements is needed, using more sensitive methods to detect clonality and monitor MRD.

Severe Fever with Thrombocytopenia Syndrome Patients with Hemophagocytic Lymphohistiocytosis Retrospectively Identified in Korea, 2008-2013.

The incidence of severe fever with thrombocytopenia syndrome (SFTS) has increased in Korea since a first report in 2013. We investigated whether SFTS existed before 2013 using real-time reverse transcription polymerase chain reaction and stored blood samples from febrile patients with thrombocytopenia. Four cases of SFTS were identified, with the earliest occurring in 2008.

Human Granulocytic Anaplasmosis as a Cause of Febrile Illness in Korea Since at Least 2006.

AbstractHuman granulocytic anaplasmosis (HGA) is a tick-borne rickettsial zoonosis with fever, thrombocytopenia, and leukopenia. HGA has been reported in Korea in 2013 but it is uncertain how long it has existed. A retrospective study was conducted on patients who underwent bone marrow examination due to fever and cytopenia, with no clear hematologic or microbiologic causes, from 2003 through 2012. Laboratory diagnosis was made by detecting 16S rRNA genes of Anaplasma phagocytophilum from the stored blood samples. Among the 70 patients, five (7.1%) HGA cases were found, and the earliest case dated back to 2006. Two cases met the diagnostic criteria of hemophagocytic lymphohistiocytosis (HLH) and were fatal. Although HGA has been prevalent in Korea since at least 2006, it is not always diagnosed and has posed a possible lethal health risk to the people in Korea. HGA should be considered as a cause of fever with cytopenia or HLH.

Evaluation of prognostic factors in patients with relapsed AML: Clonal evolution versus residual disease.

BACKGROUND: It is widely known that the prognosis of acute myeloid leukemia (AML) depends on chromosomal abnormalities. The majority of AML patients relapse and experience a dismal disease course despite initial remission. METHODS: We reviewed the medical records and laboratory findings of 55 AML patients who had relapsed between 2004 and 2013 and who had been treated at the Division of Hematology of the Pusan National University Hospital. RESULTS: The event-free survival (EFS) was related to prognostic karyotype classification at the time of diagnosis and relapse (unfavorable vs. favorable or intermediate karyotypes at diagnosis, 8.2 vs. 11.9 mo, P=0.003; unfavorable vs. favorable or intermediate karyotypes at relapse, 8.2 vs. 11.9 mo, P=0.009). The overall survival (OS) was significantly correlated with karyotype classification only at diagnosis (unfavorable vs. favorable or intermediate vs. karyotypes at diagnosis, 8.5 vs. 21.8 mo, P=0.001; unfavorable vs. favorable or intermediate karyotypes at relapse, 8.5 vs. 21.2 mo, P=0.136). A change in karyotype between diagnosis and relapse, which is regarded as a factor of resistance against treatment, was not a significant prognostic factor for OS, EFS, and post-relapse survival (PRS). A Cox proportional hazards model showed that the combined use of fludarabine, cytosine arabinoside, and granulocyte colony-stimulating factor (FLAG) as a salvage regimen, was a significant prognostic factor for OS (hazard ratio=0.399, P=0.010) and the PRS (hazard ratio=0.447, P=0.031). CONCLUSION: The karyotype classification at diagnosis predicts survival including PRS in relapsed AML patients as well as in treatment-naïve patients. We suggest that presently, administration of salvage FLAG could be a better treatment option.

Correlation of NPM1 Type A Mutation Burden With Clinical Status and Outcomes in Acute Myeloid Leukemia Patients With Mutated NPM1 Type A.

BACKGROUND: Nucleophosmin gene (NPM1) mutation may be a good molecular marker for assessing the clinical status and predicting the outcomes in AML patients. We evaluated the applicability of NPM1 type A mutation (NPM1-mutA) quantitation for this purpose. METHODS: Twenty-seven AML patients with normal karyotype but bearing the mutated NPM1 were enrolled in the study, and real-time quantitative PCR of NPM1-mutA was performed on 93 bone marrow (BM) samples (27 samples at diagnosis and 56 at follow-up). The NPM1-mutA allele burdens (represented as the NPM1-mutA/Abelson gene (ABL) ratio) at diagnosis and at follow-up were compared. RESULTS: The median NPM1-mutA/ABL ratio was 1.3287 at diagnosis and 0.092 at 28 days after chemotherapy, corresponding to a median log10 reduction of 1.7061. Significant correlations were observed between BM blast counts and NPM1-mutA quantitation results measured at diagnosis (γ=0.5885, P=0.0012) and after chemotherapy (γ=0.5106, P=0.0065). Total 16 patients achieved morphologic complete remission at 28 days after chemotherapy, and 14 (87.5%) patients showed a >3 log10 reduction of the NPM1-mutA/ABL ratio. The NPM1-mutA allele was detected in each of five patients who had relapsed, giving a median increase of 0.91-fold of the NPM1-mutA/ABL ratio at relapse over that at diagnosis. CONCLUSIONS: The NPM1-mutA quantitation results corresponded to BM assessment results with high stability at relapse, and could predict patient outcomes. Quantitation of the NPM1-mutA burden at follow-up would be useful in the management of AML patients harboring this gene mutation.

Bone marrow findings in severe fever with thrombocytopenia syndrome: prominent haemophagocytosis and its implication in haemophagocytic lymphohistiocytosis.

AIMS: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne disease caused by the SFTS virus; primary manifestations are fever, thrombocytopenia, leukopenia and gastrointestinal symptoms. Before an aetiological diagnosis is made, SFTS patients can undergo bone marrow examination due to cytopenias. Although several studies have reported on bone marrow examination in SFTS patients, most do not provide adequate details. Bone marrow findings in SFTS patients were investigated in this study. METHODS: An observational study was conducted in SFTS patients who were hospitalised between 2013 and 2014 in two university hospitals in South Korea. Patients were included in the study if SFTS was confirmed by real-time PCR for the SFTS virus and a bone marrow examination was conducted. The morphologic findings of the bone marrow samples were reviewed. RESULTS: Three cases met the study inclusion criteria. One patient died of multiple organ failure. Haemophagocytosis was evident in the bone marrow samples of all three patients. Histiocytic hyperplasia and haemophagocytosis were more pronounced in the fatal case. One patient was diagnosed as having haemophagocytic lymphohistiocytosis. CONCLUSIONS: Haemophagocytosis in the bone marrow of SFTS patients may be common. In SFTS endemic areas, SFTS should be one of the differential diagnoses of fever of unknown origin with haemophagocytosis in the bone marrow.

Incidences and Prognostic Impact of c-KIT, WT1, CEBPA, and CBL Mutations, and Mutations Associated With Epigenetic Modification in Core Binding Factor Acute Myeloid Leukemia: A Multicenter Study in a Korean Population.

BACKGROUND: To identify potential molecular prognostic markers in core binding factor (CBF) AML, we analyzed incidences and prognostic impacts of mutations in c-KIT, WT1, CEBPA, CBL, and a number of epigenetic genes in CBF AML. METHODS: Seventy one and 21 AML patients with t(8;21) and inv(16) were enrolled in this study, respectively. NPM1, CEBPA, c-KIT, IDH1/2, DNMT3A, EZH2, WT1, and CBL mutations were analyzed by direct sequencing. Patients were categorized with respect to c-KIT and WT1 mutation status, and both clinical features and prognoses were compared. RESULTS: The incidences of FLT3 internal tandem duplication (ITD), NPM1, CEBPA, IDH1/2, DNMT3A, EZH2, and CBL mutations were low (≤5%) in CBF AML patients. However, c-KIT and WT1 mutations occurred frequently (10.9% and 13.8%, respectively). t(8;21) patients with c-KIT mutations showed significantly shorter overall survival (OS) and disease free survival (DFS) periods than those without mutations (P<0.001, for both); however, although the limited number of t(8;21) patients were analyzed, WT1 mutation status did not affect prognosis significantly. Relapse or death during follow-up occurred more frequently in t(8;21) patients carrying c-KIT mutations than in those without the mutation, although the difference was significant only in a specific patient subgroup with no WT1 mutations (P=0.014). CONCLUSIONS: The incidences of mutations in epigenetic genes are very low in CBF AML; however, c-KIT and WT1 mutations occur more frequently than others. The poor prognostic impact of c-KIT mutation in t(8;21) AML patients only applies in a specific patient subgroup without WT1 mutations. The prognostic impact of WT1 mutation in CBF AML is not evident and further investigation is required.

Risk-Reducing Genetic Variant of Wilms Tumor 1 Gene rs16754 in Korean Patients With BCR-ABL1-Negative Myeloproliferative Neoplasm.

The genetic variant rs16754 of Wilms tumor gene 1 (WT1) has recently been described as an independent prognostic factor in AML patients. It is of great interest to test whether WT1 single nucleotide polymorphism can be used as a molecular marker in other types of cancer, to improve risk and treatment stratification. We performed sequencing analysis of exons 7 and 9 of WT1, which are known mutational hotspots, in a total of 73 patients with BCR-ABL1-negative myeloproliferative neoplasm (MPN) and 93 healthy controls. No previously reported WT1 mutations were identified in the present study. In Korean patients with BCR-ABL1-negative MPN, WT1 genetic variant rs16754 had no significant impact on clinical outcomes. We observed a significant difference in the allelic frequencies of WT1 rs16754 in Koreans between BCR-ABL1-negative MPN cases and healthy controls. Individuals carrying variant G alleles of WT1 rs16754 showed a relatively low prevalence of BCR-ABL1-negative MPN, compared with those carrying wild A alleles of WT1 rs16754 (Hazard ratio 0.10-0.65, P<0.05). Therefore, possession of the variant G allele of WT1 rs16754 may reduce the risk of developing BCR-ABL1-negative MPN.

The t(11;14)(q13;q32) translocation as a poor prognostic parameter for autologous stem cell transplantation in myeloma patients with extramedullary plasmacytoma.

INTRODUCTION: Fluorescence in-situ hybridization (FISH)-detected abnormalities, including del(17p), del(13q), and t(4;14), have been associated with inferior prognosis. However, there are few data about the prognostic significance of cytogenetic abnormalities for autologous stem cell transplantation (ASCT) in multiple myeloma (MM) patients with extramedullary plasmacytoma (EMP). PATIENTS AND METHODS: Between April 2004 and December 2012, 290 MM patients underwent ASCT at 3 centers. FISH data for bone marrow samples obtained at diagnosis were available for 58 patients who had EMP at diagnosis or during treatment. RESULTS: The t(11;14), t(4;14), del(13q), and 1q gain abnormalities were seen in 14.9%, 6.3%, 25.6%, and 42.9%, respectively. No t(14;16) or del(17p) cytogenetic abnormality was detected in the examined patients. Patients with t(11;14) had a lower response rate compared to patients with other cytogenetic abnormalities. EMP-specific relapse was higher in patients with t(11;14) than in patients with other cytogenetic abnormalities (42.9% vs. 10%-33.3%). Each of the 4 cytogenetic abnormalities predicted shorter median progression-free survival (6-12 months vs. 27-37 months) and shorter overall survival (16-22 months vs. 68 months or not reached) compared to no cytogenetic abnormality. The t(11;14) translocation was an important prognostic factor for both progression-free survival (hazard ratio, 25.154; P < .001) and overall survival (hazard ratio, 7.484; P = .024) in the multivariate analysis. CONCLUSION: In the current study, t(11;14), t(4;14), del(13q), and 1q gain were associated with worse survival in MM patients with EMP. The role of t(11;14) as a prognostic parameter for ASCT in MM patients with EMP should be confirmed with a large, well-designed study.

Incidence, clinical features, and prognostic impact of CALR exon 9 mutations in essential thrombocythemia and primary myelofibrosis: an experience of a single tertiary hospital in Korea.

We evaluated the incidence, clinical characteristics, and prognostic impact of calreticulin (CALR) mutations in essential thrombocythemia (ET) and primary myelofibrosis (PMF) patients. In all, 48 ET and 14 PMF patients were enrolled, and the presence of CALR mutations was analyzed by direct sequencing. Patients were classified into three subgroups according to Janus kinase 2 (JAK2) V617F and CALR mutation status, and their clinical features and prognosis were compared. CALR mutations were detected in 15 (24.2%) patients, and the incidence increased to 50.0% in 30 JAK2 V617F mutation-negative cases. These included 11 patients with three known mutations (c.1092_1143del [seven cases], c.1154_1155insTTGTC [three cases], and c.1102_1135del [one case]) and 4 patients with novel mutations. ET patients carrying CALR mutation were younger, had lower white blood cell counts, and experienced less thrombosis during follow-up than those carrying JAK2 V617F mutation, while both patient groups showed similar clinical features and prognosis. In ET patients without JAK2 V617F mutation, CALR mutation did not significantly affect clinical manifestation and prognosis. In conclusion, CALR mutation analysis could be a useful diagnostic tool for ET and PMF in 50% of the cases without JAK2 V617F mutations. The prognostic impact of CALR mutations needs further investigation.

Incidence and prognostic impact of DNMT3A mutations in Korean normal karyotype acute myeloid leukemia patients.

BACKGROUND: DNA methyltransferase 3A (DNMT3A) mutation was recently introduced as a prognostic indicator in normal karyotype (NK) AML and we evaluated the incidence and prognostic impact of DNMT3A mutations in Korean NK AML patients. METHODS: Total 67 NK AML patients diagnosed during the recent 10 years were enrolled. DNMT3A mutations were analyzed by direct sequencing and categorized into nonsynonymous variations (NSV), deleterious mutations (DM), and R882 mutation based on in silico analysis results. Clinical features and prognosis were compared with respect to DNMT3A mutation status. RESULTS: Three novel (I158M, K219V, and E177V) and two known (R736H and R882H) NSVs were identified and the latter three were predicted as DMs. DNMT3A NSVs, DMs, and R882 mutation were identified in 14.9%-17.9%, 10.3%-10.4%, and 7.5% of patients, respectively. DNMT3A mutations were frequently detected in FLT3 ITD mutated patients (P=0.054, 0.071, and 0.071 in NSV, DMs, and R882 mutation, resp.) but did not affect clinical features and prognosis significantly. CONCLUSIONS: Incidences of DNMT3A NSVs, DMs, and R882 mutation are 14.9%-17.9%, 10.3%-10.4%, and 7.5%, respectively, in Korean NK AML patients. DNMT3A mutations are associated with FLT3 ITD mutations but do not affect clinical outcome significantly in Korean NK AML patients.

Clinical relevance of high-resolution single nucleotide polymorphism array in patients with relapsed acute lymphoblastic leukemia with normal karyotype: a report of three cases.

We report three patients with normal karyotype (NK) ALL, who showed genetic aberrations as determined by high-resolution single nucleotide polymorphism array (SNP-A) analysis at both diagnosis and relapse. We evaluated the clinical relevance of the SNP-A assay for the detection of subtle changes in the size of affected genetic lesions at relapse as well as the prognostic value of the assay. In our patients, application of the SNP-A assay enabled sensitive detection of cryptic changes affecting clinically important genes in NK ALL. Therefore, this assay seems to be more advantageous compared to other conventional methods such as FISH assay, HemaVision (DNA Technology, Denmark), and conventional karyotyping for the detection of an "unstable genotype" at relapse, which may be associated with microscopic clonal evolution and poor prognosis. Further comprehensive studies are required to confirm the issues presented by our case patients in this report.