Multistep pathogenesis of chronic myelomonocytic leukemia in patients.

BACKGROUND: A multistep pathogenesis of myeloid leukemia including mutations in epigenetic, spliceosome, and signaling genes has been recently demonstrated in a preclinical model but is poorly validated in patients. METHODS: Clinical, phenotypic, and biologic features were compared between three distinct molecularly defined CMML cohorts including TET2 monomutated patients (T, n = 10), TET2/SRSF2 bimutated patients (TS, n = 19), and patients who had NRAS mutations in addition to TET2/SRSF2 comutations (TSN, n = 14). RESULTS: Median survival was 90, 45, and 9 months, respectively (p = .001). Whereas no patient in the T and TS group transformed into acute myeloid leukemia (AML), 6/14 patients in the TSN group had AML at study entry or transformed during follow-up. Leukocyte counts, blast cell counts, and LDH levels were significantly higher in TSN vs. TS and T, respectively, whereas hemoglobin and platelet values were not significantly different. Increased growth factor-independent myeloid colony formation was restricted to TSN but not found in T and TS, respectively. The proportion of patients showing in vitro myelomonocytic skewing in T, TS, and TSN was 0%, 56%, and 100%, respectively (p = .010). CONCLUSION: Our results demonstrate that the model of multistep pathogenesis in CMML can be recapitulated in patients regarding clinical, phenotypic, and biologic features.

Impact of age on the cumulative risk of transformation in patients with chronic myelomonocytic leukaemia.

In older patients with chronic myelomonocytic leukaemia (CMML) and limited life expectancy due to age and or comorbidities, it is particularly important to consider the risk of transformation for individualised treatment decisions. There is limited information on potential differences between younger and older CMML patients regarding the cumulative risk of transformation as well as haematological, molecular and biologic characteristics. We analysed data from the Austrian Biodatabase for CMML (ABCMML) to compare these parameters in 518 CMML patients. Categorisation of patients into 3 age-related groups: <60 years, 60-79 years and ≥80 years, showed a significantly lower risk of transformation at higher age by competing risk analysis, with a 4-year risk of 39%, 23% and 13%, respectively (P < .0001). The lower probability of transformation was associated with a lower percentage of blast cells in the peripheral blood (PB) of older patients. Furthermore, we provide a simple score based on age, PB blasts and platelet counts that allowed us to define subgroups of CMML patients with a different cumulative transformation risk, including a low-risk group with a transformation risk of only 5%. Our findings may facilitate reasonable treatment decisions in elderly patients with CMML.

Functional characterization, localization, and inhibitor sensitivity of the TPR-FGFR1 fusion in 8p11 myeloproliferative syndrome.

Myeloid and lymphoid neoplasms with fibroblast growth factor receptor 1 (FGFR1) abnormalities, also known as 8p11 myeloproliferative syndrome (EMS), represent rare and aggressive disorders, associated with chromosomal aberrations that lead to the fusion of FGFR1 to different partner genes. We report on a third patient with a fusion of the translocated promoter region (TPR) gene, a component of the nuclear pore complex, to FGFR1 due to a novel ins(1;8)(q25;p11p23). The fact that this fusion is a rare but recurrent event in EMS prompted us to examine the localization and transforming potential of the chimeric protein. TPR-FGFR1 localizes in the cytoplasm, although the nuclear pore localization signal of TPR is retained in the fusion protein. Furthermore, TPR-FGFR1 enables cytokine-independent survival, proliferation, and granulocytic differentiation of the interleukin-3 dependent myeloid progenitor cell line 32Dcl3, reflecting the chronic phase of EMS characterized by myeloid hyperplasia. 32Dcl3 cells transformed with the TPR-FGFR1 fusion and treated with increasing concentrations of the tyrosine kinase inhibitors ponatinib (AP24534) and infigratinib (NVP-BGJ398) displayed reduced survival and proliferation with IC50 values of 49.8 and 7.7 nM, respectively. Ponatinib, a multitargeted tyrosine kinase inhibitor, is already shown to be effective against several FGFR1-fusion kinases. Infigratinib, tested only against FGFR1OP2-FGFR1 to date, is also efficient against TPR-FGFR1. Taking its high specificity for FGFRs into account, infigratinib could be beneficial for EMS patients and should be further investigated for the treatment of myeloproliferative neoplasms with FGFR1 abnormalities.

Disruption of the ARID1B and ADAMTS6 loci due to a t(5;6)(q12.3;q25.3) in a patient with developmental delay.

Here, we report on a male patient with developmental delay, speech impairment, mild dysmorphic features, and borderline intellectual disability, bearing a de novo balanced t(5;6)(q11;q25.3). By combining FISH and long distance inverse PCR, we identified two genes, ADAMTS6 and ARID1B, which were disrupted at the translocation breakpoints. Due to the opposing transcriptional directions of the two genes, no fusion transcripts could be formed. ADAMTS6 on chromosome 5 encodes a zinc metalloprotease. To date, there has been no information about the substrates and the exact role of this enzyme protein. ARID1B on chromosome 6 is involved in chromatin remodeling and transcriptional activation and is known to play a role in neural development. To our knowledge, this is the fourth translocation involving ARID1B reported in association with intellectual disability. ARID1B haploinsufficiency has already been described in patients with intellectual disabilities with or without corpus callosum abnormalities, Coffin-Siris syndrome and autism (OMIM 614562 and OMIM 614556). A review of patients with ARID1B mutations reveals their broad phenotypic variability. The phenotype of the present patient is of the mildest described to date and further underscores this observation. We conclude that the most prominent and consistent clinical findings in patients with ARID1B haploinsufficiency are developmental delay, speech impairment and intellectual disability and propose that patients with unresolved genetic background and these clinical findings should be considered for ARID1B mutation screening.

The Austrian biodatabase for chronic myelomonocytic leukemia (ABCMML) : A representative and useful real-life data source for further biomedical research.

In the Austrian biodatabase for chronic myelomonocytic leukemia (ABCMML) clinicolaboratory real-life data have been captured from 606 CMML patients from 14 different hospitals over the last 30 years. It is the only large biodatabase worldwide in which functional methods such as semisolid in vitro cultures complement modern molecular methods such as next generation sequencing. This provides the possibility to comprehensively study the biology of CMML. The aim of this study was to compare patient characteristics with published CMML cohorts and to validate established prognostic parameters in order to examine if this real-life database can serve as a representative and useful data source for further research. After exclusion of patients in transformation characteristics of 531 patients were compared with published CMML cohorts. Median values for age, leukocytes, hemoglobin, platelets, lactate dehydrogenase (LDH) and circulating blasts were within the ranges of reported CMML series. Established prognostic parameters including leukocytes, hemoglobin, blasts and adverse cytogenetics were able to discriminate patients with different outcome. Myeloproliferative (MP) as compared to myelodysplastic (MD)-CMML patients had higher values for circulating blasts, LDH, RAS-pathway mutations and for spontaneous myelomonocytic colony growth in vitro as well as more often splenomegaly. This study demonstrates that the patient cohort of the ABCMML shares clinicolaboratory characteristics with reported CMML cohorts from other countries and confirms phenotypic and genotypic differences between MP-CMML and MD-CMML. Therefore, results obtained from molecular and biological analyses using material from the national cohort will also be applicable to other CMML series and thus may have a more general significance.

Overexpression of the proneural transcription factor ASCL1 in chronic lymphocytic leukemia with a t(12;14)(q23.2;q32.3).

BACKGROUND: Translocations of the IGH locus on 14q32.3 are present in about 8% of patients with chronic lymphocytic leukemia (CLL) and contribute to leukemogenesis by deregulating the expression of the IGH-partner genes. Identification of these genes and investigation of the downstream effects of their deregulation can reveal disease-causing mechanisms. CASE PRESENTATION: We report on the molecular characterization of a novel t(12;14)(q23.2;q32.3) in CLL. As a consequence of the rearrangement ASCL1 was brought into proximity of the IGHJ-Cµ enhancer and was highly overexpressed in the aberrant B-cells of the patient, as shown by qPCR and immunohistochemistry. ASCL1 encodes for a transcription factor acting as a master regulator of neurogenesis, is overexpressed in neuroendocrine tumors and a promising therapeutic target in small cell lung cancer (SCLC). Its overexpression has also been recently reported in acute adult T-cell leukemia/lymphoma.To examine possible downstream effects of the ASCL1 upregulation in CLL, we compared the gene expression of sorted CD5+ cells of the translocation patient to that of CD19+ B-cells from seven healthy donors and detected 176 significantly deregulated genes (Fold Change ≥2, FDR p ≤ 0.01). Deregulation of 55 genes in our gene set was concordant with at least two studies comparing gene expression of normal and CLL B-lymphocytes. INSM1, a well-established ASCL1 target in the nervous system and SCLC, was the gene with the strongest upregulation (Fold Change = 209.4, FDR p = 1.37E-4).INSM1 encodes for a transcriptional repressor with extranuclear functions, implicated in neuroendocrine differentiation and overexpressed in the majority of neuroendocrine tumors. It was previously shown to be induced in CLL cells but not in normal B-cells upon treatment with IL-4 and to be overexpressed in CLL cells with unmutated versus mutated IGHV genes. Its role in CLL is still unexplored. CONCLUSION: We identified ASCL1 as a novel IGH-partner gene in CLL. The neural transcription factor was strongly overexpressed in the patient's CLL cells. Microarray gene expression analysis revealed the strong upregulation of INSM1, a prominent ASCL1 target, which was previously shown to be induced in CLL cells upon IL-4 treatment. We propose further investigation of the expression and potential role of INSM1 in CLL.

Characterization of a newly identified ETV6-NTRK3 fusion transcript in acute myeloid leukemia.

BACKGROUND: Characterization of novel fusion genes in acute leukemia is important for gaining information about leukemia genesis. We describe the characterization of a new ETV6 fusion gene in acute myeloid leukemia (AML) FAB M0 as a result of an uncommon translocation involving chromosomes 12 and 15. METHODS: The ETV6 locus at 12p13 was shown to be translocated and to constitute the 5' end of the fusion product by ETV6 break apart fluorescence in situ hybridisation (FISH). To identify a fusion partner 3' rapid amplification of cDNA-ends with polymerase chain reaction (RACE PCR) was performed followed by cloning and sequencing. RESULTS: The NTRK3 gene on chromosome 15 was found to constitute the 3' end of the fusion gene and the underlying ETV6-NTRK3 rearrangement was verified by reverse transcriptase PCR. No RNA of the reciprocal NTRK3-ETV6 fusion gene could be detected. CONCLUSION: We have characterized a novel ETV6-NTRK3 fusion transcript which has not been previously described in AML FAB M0 by FISH and RACE PCR. ETV6-NTRK3 rearrangements have been described in secretory breast carcinoma and congenital fibrosarcoma.

Intratumoral lymphocyte density in serous ovarian carcinoma is superior to ERCC1 expression for predicting response to platinum-based therapy.

Intratumoral immune cells and ERCC1 expression are likely to play a role in the response of ovarian carcinoma to chemotherapy, but their impact on therapy outcome is still unclear. Therefore, 41 cases of optimally resected high grade serous ovarian carcinomas were examined retrospectively for stromal and intraepithelial lymphocyte populations and ERCC1 status in relation to response to platinum-based therapy. Based on RECIST criteria, 27 patients were classified as responsive and 14 as therapy resistant, respectively. Using immunohistochemistry for CD3, CD8, CD4, TIA1, MUM1 and FOX P3 on representative tumor sections, we quantitatively evaluated the intratumoral density of lymphocyte subpopulations. In addition, ERCC1 protein and mRNA expression were determined by immunohistochemistry using the Steffensen score and quantitative RT-PCR, respectively. Furthermore, ERCC1 SNP's C8092A and codon 118 were analysed. Response to chemotherapy was significantly associated with higher numbers of stromal CD3+ (mean 21.33 lymphocytes/HPF versus 8.21 lymphocytes/HPF, p = 0.002) and CD8+ lymphocytes (mean 9.22 lymphocytes/HPF versus 4.57 lymphocytes/HPF, p = 0.013). Counts of intraepithelial CD3+ and CD8+ lymphocytes, stromal and intraepithelial FOXP3+ and TIA1+ cells, CD4+ lymphocytes, and MUM1+ plasma cells did not reach statistical significance. Neither ERCC1 protein expression (p = 0.232) nor SNPs codon 118 and C8092A of the ERCC1 gene (p = 0.269 and p = 0.543) showed an association with therapy response. The same was true for ERCC1 mRNA levels (p = 0.896), probably due to intratumoral lymphocyte contamination. In conclusion, the density of CD3+ and CD8+ T-cells in tumor stroma proved to be a significant predictor for response to platinum-based therapy, whereas examination of ERCC1 failed to identify therapy-responsive patients.

Factor V Leiden, prothrombin G20210A, and methylenetetrahydrofolate reductase C677T mutations are not associated with chronic limb ischemia: the Linz Peripheral Arterial Disease (LIPAD) study.

OBJECTIVE: Factor V G1691A (Leiden), prothrombin G20210A, and methylenetetrahydrofolate reductase (MTHFR) C677T mutations are considered risk factors for venous thromboembolism. It remains to be characterized whether the presence of these relatively common mutations poses a risk for peripheral arterial disease (PAD). Therefore, we intended to test, by conducting a case-control study, the hypothesis that PAD was associated with an increased prevalence of factor V G1691A, prothrombin G20210A, and MTHFR C677T mutations. METHODS: The study comprised 433 patients admitted for inpatient diagnostics and treatment of PAD in patients with chronic limb ischemia. Patients with acute ischemia or malignancy were excluded. A total of 433 control subjects matched to the patients with PAD in a 1:1 design by sex, age (+/-2 years), and diabetes mellitus status were recruited. Factor V G1691A, prothrombin G20210A, and MTHFR C677T genotypes were assessed by polymerase chain reaction. RESULTS: For the factor V G1691A polymorphism, the genotype frequencies in PAD patients were 92.8% GG (normal homozygotes = wild type) and 7.2% GA (mutant heterozygotes), and in control subjects they were 94.0% GG and 6.0% GA (chi 2 test; P = .493). The distribution of the prothrombin G20210A genotypes was 96.3% GG (normal homozygotes = wild type) and 3.7% GA (mutant heterozygotes) in PAD patients and was 97.2% GG and 2.8% GA in control subjects (chi 2 test; P = .442). Genotype frequencies for the MTHFR C677T polymorphism were 47.8% CC (normal homozygotes = wild type), 43.4% CT (mutant heterozygotes), and 8.8% TT (mutant homozygotes) in PAD patients, compared with 47.1% CC, 44.1% CT, and 8.8% TT in control subjects (chi 2 test; P = .977). Accordingly, as determined by logistic regression analysis, no significant odds ratios for heterozygous or homozygous genotypes of the three polymorphisms could be observed. CONCLUSIONS: PAD was not associated with an increased prevalence of factor V G1691A, prothrombin G20210A, and MTHFR C677T mutations in the population studied. Thus, there is no indication that of one of these mutations may be a risk factor for chronic limb ischemia. However, the role of these mutations in acute limb ischemia remains to be clarified.