ICSH: on board for new projects

The International Council for Standardization in Hematology (ICSH) is a not-for-profit organization aimed at improving global quality and harmonization of analytical methods, and achieving reliable and reproducible results in diagnostic hematology. ICSH co-ordinates Working Groups of experts to examine laboratory methods and instruments for hematological analyses, and co-operates with different international organizations which have similar scientific goals. Among seven ongoing approved projects, three ICSH projects have been selected and will be presented in the ICSH session at the XXVIIth ISLH International Symposium on Technological Innovations in Laboratory Hematology in The Hague, on May 2014. The project on 'Guideline for flow cytometric evaluation of patients with suspected acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS)' covers different aspects of the application of immunophenotyping by multiparameter flow cytometry (MFC) in the diagnosis of AML and MDS including integration into multimodal diagnostic workflow, quality control, antibody selection, interpretation of findings, reporting, and personnel. Data from the pilot study of the project for 'International Standardization of Hematology Reporting Units' suggest that there is a wide variation in reporting units for the routine blood cell count and highlights the areas of nomenclature and units of measurement where standardization is necessary and feasible, such as units for cell counts, white cell differentials, and hemoglobin concentration. The project on 'Standardization of HbA2 measurement and its implications for clinical practice' starts from the observation that different instruments give different results for hemoglobin A2; it is aimed at producing recommendations as to how instrument manufacturers and laboratories should assess their equipment before using it to analyze patient samples. These projects are examples of how the ICSH represents a great opportunity for scientists involved in hematology laboratory to participate in a process of expert collaboration and discussion all around the world.

Revisiting guidelines for integration of flow cytometry results in the WHO classification of myelodysplastic syndromes-proposal from the International/European LeukemiaNet Working Group for Flow Cytometry in MDS

Definite progress has been made in the exploration of myelodysplastic syndromes (MDS) by flow cytometry (FCM) since the publication of the World Health Organization 2008 classification of myeloid neoplasms. An international working party initiated within the European LeukemiaNet and extended to include members from Australia, Canada, Japan, Taiwan and the United States has, through several workshops, developed and subsequently published consensus recommendations. The latter deal with preanalytical precautions, and propose small and large panels, which allow evaluating immunophenotypic anomalies and calculating myelodysplasia scores. The current paper provides guidelines that strongly recommend the integration of FCM data with other diagnostic tools in the diagnostic work-up of MDS.

BAALC expression: a suitable marker for prognostic risk stratification and detection of residual disease in cytogenetically normal acute myeloid leukemia

High brain and acute leukemia, cytoplasmic (BAALC) expression defines an important risk factor in cytogenetically normal acute myeloid leukemia (CN-AML). The prognostic value of BAALC expression in relation to other molecular prognosticators was analyzed in 326 CN-AML patients (<65 years). At diagnosis, high BAALC expression was associated with prognostically adverse mutations: FLT3 internal tandem duplication (FLT3-ITD) with an FLT3-ITD/FLT3 wild-type (wt) ratio of ⩾0.5 (P=0.001), partial tandem duplications within the MLL gene (MLL-PTD) (P=0.002), RUNX1 mutations (mut) (P<0.001) and WT1mut (P=0.001), while it was negatively associated with NPM1mut (P<0.001). However, high BAALC expression was also associated with prognostically favorable biallelic CEBPA (P=0.001). Survival analysis revealed an independent adverse prognostic impact of high BAALC expression on overall survival (OS) and event-free survival (EFS), and also on OS when eliminating the effect of allogeneic stem cell transplantation (SCT) (OS^TXcens). Furthermore, we analyzed BAALC expression in 416 diagnostic and follow-up samples of 66 patients. During follow-up, BAALC expression correlated with mutational load or expression levels, respectively, of other minimal residual disease markers: FLT3-ITD (r=0.650, P<0.001), MLL-PTD (r=0.728, P<0.001), NPM1mut (r=0.599, P<0.001) and RUNX1mut (r=0.889, P<0.001). Moreover, a reduction in BAALC expression after the second cycle of induction chemotherapy was associated with improved EFS. Thus, our data underline the utility of BAALC expression as a marker for prognostic risk stratification and detection of residual disease in CN-AML.

High number of additional genetic lesions in acute myeloid leukemia with t(8;21)/RUNX1-RUNX1T1: frequency and impact on clinical outcome

t(8;21)/RUNX1-RUNX1T1-positive acute myeloid leukemia (AML) is prognostically favorable; however, outcome is heterogeneous. We analyzed 139 patients with t(8;21)/RUNX1-RUNX1T1-positive AML (de novo: n=117; therapy-related: n=22) to determine frequency and prognostic impact of additional genetic abnormalities. All patients were investigated for mutations (mut) in ASXL1, FLT3, KIT, NPM1, MLL, IDH1, IDH2, KRAS, NRAS, CBL and JAK2. Sixty-nine of 139 cases (49.6%) had 1 mutation in addition to RUNX1-RUNX1T1, and 23/139 (16.5%) had ⩾2 additional mutations. Most common were KITmut (23/139; 16.5%), NRASmut (18/139; 12.9%) and ASXL1mut (16/139; 11.5%). FLT3-ITD, FLT3-TKDmut, CBLmut, KRASmut, IDH2mut and JAK2mut were found in 2.9-5.0%. Additional chromosomal abnormalities (ACAs) were found in 97/139 (69.8%). Two-year overall survival (OS) was 73.4% in 111 intensively treated patients. KITD816mut negatively impacted on OS in de novo AML (2-year OS: 59.1% vs 82.0%, P=0.03), ASXL1mut on EFS (de novo AML: 20% vs 59.1%, P=0.011; total cohort: 28.6% vs 56.7%, P=0.021). Sex chromosome loss was favorable (2-year EFS: 66.9% vs 43.0%, P=0.031), whereas +8 was adverse on EFS (2-year EFS: 26.7% vs 55.9%, P=0.02). In conclusion, t(8;21)/RUNX1-RUNX1T1-positive AML shows a high frequency of additional genetic alterations. Investigation for KITD816 and ASXL1mut combined with investigation of ACAs is recommended in t(8;21)/RUNX1-RUNX1T1-positive AML because of the prognostic significance of these parameters.

SF3B1 mutations correlated to cytogenetics and mutations in NOTCH1, FBXW7, MYD88, XPO1 and TP53 in 1160 untreated CLL patients

We analyzed a large cohort of 1160 untreated CLL patients for novel genetic markers (SF3B1, NOTCH1, FBXW7, MYD88, XPO1) in the context of molecular, immunophenotypic and cytogenetic data. NOTCH1 mutations (mut) (12.3%), SF3B1mut (9.0%) and TP53mut (7.1%) were more frequent than XPO1mut (3.4%), FBXW7mut (2.5%) and MYD88mut (1.5%). SF3B1mut, NOTCH1mut, TP53mut and XPO1mut were highly correlated to unmutated, whereas MYD88mut were associated with mutated IGHV status. Associations of diverse cytogenetic aberrations and mutations emerged: (1) SF3B1mut with del(11q), (2) NOTCH1mut and FBXW7mut with trisomy 12 and nearly exclusiveness of SF3B1mut, (3) MYD88mut with del(13q) sole and low frequencies of SF3B1mut, NOTCH1mut and FBXW7mut. In patients with normal karyotype only SF3B1mut were frequent, whereas NOTCH1mut rarely occurred. An adverse prognostic impact on time to treatment (TTT) and overall survival (OS) was observed for SF3B1mut, NOTCH1mut and TP53 disruption. In multivariate analyses SF3B1mut, IGHV mutational status and del(11q) were the only independent genetic markers for TTT, whereas for OS SF3B1mut, IGHV mutational status and TP53 disruption presented with significant impact. Finally, our data suggest that analysis of gene mutations refines the risk stratification of cytogenetic prognostic subgroups and confirms data of a recently proposed model integrating molecular and cytogenetic data.

Landscape of genetic lesions in 944 patients with myelodysplastic syndromes

High-throughput DNA sequencing significantly contributed to diagnosis and prognostication in patients with myelodysplastic syndromes (MDS). We determined the biological and prognostic significance of genetic aberrations in MDS. In total, 944 patients with various MDS subtypes were screened for known/putative mutations/deletions in 104 genes using targeted deep sequencing and array-based genomic hybridization. In total, 845/944 patients (89.5%) harbored at least one mutation (median, 3 per patient; range, 0-12). Forty-seven genes were significantly mutated with TET2, SF3B1, ASXL1, SRSF2, DNMT3A, and RUNX1 mutated in >10% of cases. Many mutations were associated with higher risk groups and/or blast elevation. Survival was investigated in 875 patients. By univariate analysis, 25/48 genes (resulting from 47 genes tested significantly plus PRPF8) affected survival (P<0.05). The status of 14 genes combined with conventional factors revealed a novel prognostic model ('Model-1') separating patients into four risk groups ('low', 'intermediate', 'high', 'very high risk') with 3-year survival of 95.2, 69.3, 32.8, and 5.3% (P<0.001). Subsequently, a 'gene-only model' ('Model-2') was constructed based on 14 genes also yielding four significant risk groups (P<0.001). Both models were reproducible in the validation cohort (n=175 patients; P<0.001 each). Thus, large-scale genetic and molecular profiling of multiple target genes is invaluable for subclassification and prognostication in MDS patients.

The role of different genetic subtypes of CEBPA mutated AML

The prognostic impact of mutations in the CCAAT/enhancer binding protein α (CEBPA) gene was evaluated in the context of concomitant molecular mutations and cytogenetic aberrations in acute myeloid leukemia (AML). CEBPA was screened in a cohort of 2296 adult AML cases. Of 244 patients (10.6%) with CEBPA mutations, 140 cases (6.1%) were single-mutated (CEBPAsm) and 104 cases (4.5%) were double-mutated (CEBPAdm). Cytogenetic analysis revealed normal karyotype in 172/244 (70.5%) of CEBPAmut cases, whereas in 72/244 cases (29.5%) at least one cytogenetic aberration was detected. Concurrent molecular mutations were seen less frequently in CEBPAdm than in CEBPAsm AML cases (69.2% vs 88.6% P<0.001). In detail, the spectrum of concurrent mutations was different in both groups with the frequent occurrence of GATA1 and WT1 mutations in CEBPAdm patients. In contrast, FLT3-ITD, NPM1, ASXL1 and RUNX1 mutations were detected more frequently in CEBPAsm cases. Favorable outcome was restricted to CEBPAdm cases and remained an independent prognostic factor for a favorable outcome in multivariate analysis (hazard ratio: 0.438, P=0.020). Outcome in CEBPAsm cases strongly depended on concurrent FLT3-ITD. In conclusion, we propose that only CEBPAdm should be considered as an entity in the WHO classification of AML and should be clearly distinguished from CEBPAsm AML.

SETBP1 mutations occur in 9% of MDS/MPN and in 4% of MPN cases and are strongly associated with atypical CML, monosomy 7, isochromosome i(17)(q10), ASXL1 and CBL mutations

Chronic myeloid malignancies are categorized to the three main categories myeloproliferative neoplasms (MPNs), myelodysplastic syndromes (MDSs) and MDS/MPN overlap. So far, no specific genetic alteration profiles have been identified in the MDS/MPN overlap category. Recent studies identified mutations in SET-binding protein 1 (SETBP1) as novel marker in myeloid malignancies, especially in atypical chronic myeloid leukemia (aCML) and related diseases. We analyzed SETBP1 in 1 130 patients with MPN and MDS/MPN overlap and found mutation frequencies of 3.8% and 9.4%, respectively. In particular, there was a high frequency of SETBP1 mutation in aCML (19/60; 31.7%) and MDS/MPN unclassifiable (MDS/MPN, U; 20/240; 9.3%). SETBP1 mutated (SETBP1mut) patients showed significantly higher white blood cell counts and lower platelet counts and hemoglobin levels than SETBP1 wild-type patients. Cytomorphologic evaluation revealed a more dysplastic phenotype in SETBP1mut cases as compared with wild-type cases. We confirm a significant association of SETBP1mut with -7 and isochromosome i(17)(q10). Moreover, SETBP1mut were strongly associated with ASXL1 and CBL mutations (P<0.001 for both) and were mutually exclusive of JAK2 and TET2 mutations. In conclusion, SETBP1mut add an important new diagnostic marker for MDS/MPN and in particular for aCML.