Genetic mutations associated with blood count abnormalities in myeloid neoplasms.

INTRODUCTION: Myelodysplastic syndromes (MDS) predominantly present with varying degrees of cytopenia, while myelodysplastic syndromes/myeloproliferative neoplasms (MDS/MPN) exhibit proliferative features. Genetic defects underlying different complete blood count (CBC) alterations remain to be defined. OBJECTIVE: We aimed to evaluate mutations and impacts on abnormal blood counts in MDS and MDS/MPN. METHOD: MDS and MDS/MPN patients were recruited and sequenced by targeted next-generation sequencing. Clinical parameters, especially CBC, were evaluated for the association with genetic abnormalities and clinical outcomes. RESULTS: A total of 168 patients with myeloid neoplasms were recruited (92 cases of low-risk MDS, 57 cases of high-risk MDS and 19 cases of MDS/MPN). Compared to low-risk MDS and MDS/MPN, patients with high-risk MDS were presented with more severe neutropenia with 17.5% showing absolute neutrophil counts (ANC) lower than 0.5 × 109/L. Patients with MDS/MPN more commonly harboured mutations and had a higher number of mutations per case than low-risk MDS (94.7% vs. 56.5%; p < 0.001 and 3 vs. 1; p < 0.001, respectively). Patients with SF3B1 mutations showed lower haemoglobin levels than wild-type (7.9 vs. 8.4 g/dL, p = 0.02), but were associated with normal platelet counts (286 vs. 93 × 109/L; p < 0.001). Patients with U2AF1 mutations were associated with more severe leukopenia than wild-type (3 vs. 4.18 × 109/L; p = 0.02). KRAS mutations were associated with monocytosis (p < 0.001). Multivariate analysis revealed high-risk MDS, MDS/MPN, severe neutropenia (ANC < 0.5 × 109/L), and mutations in ASXL1 and SETBP1 were associated with inferior survival outcomes. CONCLUSION: Certain mutations were related to more severe anaemia, lower white blood cell count or monocytosis in Asian MDS and MDS/MPN patients.

Excellent Prognosis of Low-Risk Myelodysplastic Syndromes (MDS) Without Detectable Myeloid-Related Mutations.

BACKGROUND: Unexplained cytopenia (UC) and low-risk myelodysplastic syndrome (MDS) are distinguished mainly by morphologic dysplasia, which sometimes shows inter-observer discrepancy. We hypothesized that gene mutations are strong prognostic factors for these low-risk patients. MATERIALS AND METHODS: We enrolled patients from 4 medical centers with unexplained cytopenia of at least 1 lineage. Diagnosis of low-risk MDS was made according to WHO 2016 classification and a revised international prognostic scoring system (R-IPSS) score of ≤ 3.5. DNA was extracted from bone marrow or blood and sequenced by targeted next generation sequencing (NGS). RESULTS: One hundred twenty-one patients were recruited: 25% with UC and 75% with low-risk MDS. Complete blood counts were similar, but low-risk MDS patients carried higher numbers of mutations (1 vs. 0; P = .04) than UC patients. Overall, the most frequent mutated genes were TET2 (14.6%), SF3B1 (12.2%), and ASXL1 (9.7%). Survival rates of low-risk MDS patients versus UC patients were not significantly different. UC patients and low-risk MDS patients without genetic abnormalities showed superior 5-year progression free survival compared to MDS patients with mutations (100% vs. 76.0%; P = .005). Overall, ASXL1 mutations were associated with decreased 4-year overall survival compared to wild-type (59% vs. 31%; P = .01). In a multivariate analysis, ASXL1 and DNMT3A mutations in low-risk MDS patients were associated with a higher risk of disease progression with hazard ratios of 7.88 (95% CI 1.76-35.32, P = .01) and 7.45 (95% CI 1.61-34.46, P = .01), respectively. CONCLUSION: Mutation detection is important for proper risk stratification of patients presenting with idiopathic cytopenia.

Frequent mutations in HLA and related genes in extranodal NK/T cell lymphomas.

Extranodal NK/T cell lymphomas (ENKTCLs) are aggressive Epstein-Barr virus-associated T/NK neoplasms that predominantly affect Asians. To explore the causative somatic events, we conducted a comprehensive genetic analysis of 19 ENKTCL patients by whole-genome (N = 2), whole-exome (N = 16), and targeted sequencing (N = 15). Commonly deregulated gene pathways in ENKTCLs included epigenetic modifiers (58%, 11/19) followed by human leukocyte antigens (HLAs) and related genes including HLA-A, B2M, TAP1, CD274, and PDCD1LG2 (32%, 6/19), and JAK-STAT pathway (26%, 5/19). Conspicuously, loss-of-function mutations in HLA-A were recurrently identified in ENKTCLs (16%, 3/19). HLA protein expression was examined by immunohistochemistry in 16 patients and lower expression was associated with advanced stages at presentation (p = .007). In conclusion, the defective antigen presenting pathway is common and related to disease progression, suggesting immune escape as a pathogenic mechanism of ENKTCLs.

Novel DDX41 variants in Thai patients with myeloid neoplasms.

Germline DDX41 mutations were recently reported to cause MDS/AML and donor-derived leukemia after transplantation. While previously described in Western countries, DDX41 variants have not been reported in a Southeast Asian population. We performed targeted sequencing of blood or bone marrow samples from 109 Thai patients with myeloid malignancies. Among the 109 patients (75 MDS, 8 MPN, 11 MDS/MPN and 15 AML), the most frequent mutations were in ASXL1 (17.4%), TET2 (16.5%) and SRSF2 (12.8%), respectively. DDX41 variants were detectable in six (5.5%) cases. Four patients exhibited three presumable germline DDX41 mutations: p.S21fs (n = 2), p.F235fs (n = 1), and p.R339H (n = 1). While p.S21fs was previously reported in myeloid neoplasm, the latter two variants have not been described. Two of these cases harbored concomitant probable germline/somatic DDX41 mutations (p.S21fs/p.R525H and p.R339H/p.K494T), while the other two patients carried only somatic mutations (p.R525H and p.F438L). The p.K494T and p.F438L variants have not been previously reported. In patients with DDX41 alterations, the diagnoses were MDS with excess blasts (4), secondary AML (1) and low-risk MDS (1). In conclusion, we identified DDX41 variants in Thai patients with myeloid malignancies in which these variants could be used to assess predisposition to MDS in Southeast Asia.

Frequent germline mutations of HAVCR2 in sporadic subcutaneous panniculitis-like T-cell lymphoma.

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare subtype of peripheral T-cell lymphoma affecting younger patients and associated with hemophagocytic lymphohistiocytosis. To clarify the molecular pathogenesis of SPTCL, we analyzed paired tumor and germline DNAs from 13 patients by whole-exome sequencing. All cases were Asians and were phenotypically sporadic with no family history of SPTCL. Consistent with a recent report, germline mutations in HAVCR2, encoding T-cell immunoglobulin mucin 3 (TIM3), were identified in 11 of 13 (85%) cases. All mutated cases were primary SPTCL, whereas the 2 cases without mutation were secondary SPTCL associated with underlying diseases, including viral infection and autoimmune disease. Ten patients harbored homozygous p.Y82C mutations, and 1 showed compound heterozygous mutations (p.Y82C and p.T101I). Both missense mutations altered highly conserved residues located in the extracellular immunoglobulin variable-like domain. According to the Genome Aggregation Database of >138 500 general individuals, both mutations were documented with minor allele frequencies < 0.007, indicating remarkable enrichment of these HAVCR2 alleles in SPTCL. SPTCL cells also harbored somatic mutations (6.2 per patient) that are frequently identified in genes associated with epigenetic regulation and signal transduction. In conclusion, individuals harboring biallelic HAVCR2 (TIM3) germline mutations were highly susceptible to sporadic SPTCL, which was also associated with clonal somatic mutations.

Decoding the pathophysiology and the genetics of multiple myeloma to identify new therapeutic targets.

In recent years, significant progress has been achieved in the characterization of the transcriptional profiles, gene mutations and structural chromosomal lesions in myeloma cells. These studies have identified many candidate therapeutic targets, which are recurrently deregulated in myeloma cells. However, these targets do not appear, at least individually, to represent universal driver(s) of this disease. Furthermore, evaluation of these recurrent lesions does not suggest that they converge to a single molecular pathway. Detailed integration of molecular and functional data for these candidate targets and pathways will hopefully dissect which of them play more critical roles for each of the different individual molecular defined subtypes of this disease. This review focuses on how recent updates in our understanding of myeloma pathogenesis and molecular characterization may impact ongoing and future efforts to develop new therapeutics for this disease.

New proteasome inhibitors in myeloma.

Proteasome inhibition has a validated role in cancer therapy since the successful introduction of bortezomib for the treatment of multiple myeloma (MM) and mantle cell lymphoma, leading to the development of second-generation proteasome inhibitors (PI) for MM patients in whom currently approved therapies have failed. Five PIs have reached clinical evaluation, with the goals of improving efficacy and limiting toxicity, including peripheral neuropathy (PN). Carfilzomib, an epoxyketone with specific chymothrypsin-like activity, acts as an irreversible inhibitor and was recently FDA approved for the response benefit seen in relapsed and refractory MM patients previously treated with bortezomib, thalidomide and lenalidomide. ONX-0912 is now under evaluation as an oral form with similar activity. The boronate peptides MLN9708 and CEP-18770 are orally bioactive bortezomib analogs with prolonged activity and greater tissue penetration. NPI-0052 (marizomib) is a unique, beta-lactone non-selective PI that has been shown to potently overcome bortezomib resistance in vitro. All of these second-generation PIs demonstrate encouraging anti-MM activity and appear to reduce the incidence of PN, with clinical trials ongoing.

Prevalence of monoclonal gammopathy of undetermined significance in Thailand.

Individuals with monoclonal gammopathy of undetermined significance (MGUS) develop multiple myeloma and related malignancies at the rate of 1% per year. Given differences in ethnicity, data on prevalence and risk factors of MGUS in Thai population will be helpful in understanding the pathogenesis of plasma cell disorders and designing an early cancer detection strategy. Subjects of 50 years or older were included. Demographic data and suspected risk factors were collected. Monoclonal proteins were detected using serum protein electrophoresis. Serum was obtained from 3,260 participants; 1,104 males (33.9%) and 2,156 females (66.1%). The median age was 57 years (range 50-93 years). Monoclonal proteins were detectable in 2.3% (95% confidence interval [CI] 1.8-2.8). M spikes were found in gamma- and beta-globulin regions in 50 (1.5%) and 25 (0.8%) subjects, respectively. The prevalence of MGUS in subjects 50-59, 60-69, and 70 years or older was 2.0% (41/1,975), 2.6% (22/851), and 2.8% (12/434), respectively. By multivariate analysis, MGUS was associated with living outside Bangkok (odds ratio 2.25, 95% CI 1.11-4.58). The overall prevalence of MGUS in the Thai population was 2.3%, which was lower than that in Western countries, but comparable to that in Japan.

Dengue hemorrhagic fever in a peripheral blood stem cell transplant recipient: the first case report.

Dengue infection, a mosquito-borne infectious disease in tropical and subtropical areas, has recently become an emerging global disease. The clinical course of dengue infection may be unfavorable in immunocompromised patients. In this report, we present a 16-year old female patient with acute myeloid leukemia who received allogeneic peripheral blood stem cell transplant five months prior to presentation. She was hospitalized at King Chulalongkorn Memorial Hospital, Bangkok, Thailand, due to fever, headache, and myalgia for one day. During hospitalization, she developed capillary leakage syndrome and progressive thrombocytopenia. A diagnosis of dengue hemorrhagic fever was made and confirmed by positive dengue serology and polymerase chain reaction testing. She made a full recovery 14 days after hospitalization. Our case possibly acquired dengue virus from infected mosquitoes while visiting her relatives four days before her present illness. In conclusion, this is the first reported case of dengue hemorrhagic fever in a peripheral blood stem cell transplant recipient. In addition, we review all previous reports of dengue infection in organ transplant recipients.