Acquired Clotting Factor Deficits During Treatment with Asparaginase in an Institutional Cohort.

We invariably see prolongation of activated partial thromboplastin time in patients treated with asparaginase in our clinical practice, but have noted that, contrary to hypofibrinogenemia and low antithrombin, clotting times' prolongation by asparaginase is largely unreported in the literature and guidelines and is not widely known to clinicians. We report on aPTT prolongations in a small cohort of patients, and on their origin, as investigated by measurements of clotting factors, fibrinogen, and D-dimers before and after asparaginase administration. We observed significant reductions in FIX and FXI (median post-treatment values of 27 IU/dl and 52 IU/dl, respectively), confirming one previous observation. A decrease in FXII was less pronounced but contributed to the prolonged aPTTs (FXII has no effect on in vivo haemostasis). The factor deficits are not due to consumption, as evidenced by unchanged D-dimer levels, and are, therefore, probably caused by disturbed factor synthesis. Our observations and insights contribute to elucidation of the profile of clotting assays during asparaginase treatment, and thus, to optimally monitor for undesirable events or steer situations of therapeutic anticoagulation without the risk of suboptimal or excessive anticoagulation.

Description of an Institutional Cohort of Myeloid Neoplasms Carrying ETV6-Locus Deletions or ETV6 Rearrangements.

The gene encoding for transcription factor ETV6 presents recurrent lesions in hematologic neoplasms, most notably the ETV6-RUNX1 rearrangement in childhood B-ALL. The role of ETV6 for normal hematopoiesis is unknown, but loss of its function probably participates in oncogenic procedures. In myeloid neoplasms, ETV6-locus (12p13) deletions are rare but recurrent; ETV6 translocations are even rarer, but those reported seem to have phenotype-defining consequences. We herein describe the genetic and hematologic profile of myeloid neoplasms with ETV6 deletions (10 cases), or translocations (4 cases) diagnosed in the last 10 years in our institution. We find complex caryotype to be the most prevalent cytogenetics among patients with 12p13 deletion (8/10 patients), with most frequent coexisting anomalies being monosomy 7 or deletion 7q32 (5/10), monosomy 5 or del5q14-15 (5/10), and deletion/inversion of chromosome 20 (5/10), and most frequent point mutation being TP53 mutation (6/10 patients). Mechanisms of synergy of these lesions are unknown. We describe the entire genetic profile and hematologic phenotype of cases with extremely rare ETV6 translocations, confirming the biphenotypic T/myeloid nature of acute leukemia associated to ETV6-NCOA2 rearrangement, the association of t (1;12) (p36; p13) and of the CHIC2-ETV6 fusion with MDS/AML, and the association of the ETV6-ACSL6 rearrangement with myeloproliferative neoplasm with eosinophilia. Mutation of the intact ETV6 allele was present in two cases and seems to be subclonal to the chromosomal lesions. Decoding the mechanisms of disease related to ETV6 haploinsufficiency or rearrangements is important for the understanding of pathogenesis of myeloid neoplasms and fundamental research must be guided by observational cues.

Single-center, observational study of AML/MDS-EB with IDH1/2 mutations: genetic profile, immunophenotypes, mutational kinetics and outcomes.

OBJECTIVE: IDH1/2 mutations, intervening in epigenetic procedures, are frequently encountered in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). Knowledge of the genetics, immunophenotypes, and mutational kinetics of IDH1/2-mutated AML can contribute to the understanding of AML clonal architecture and inform therapeutics and monitoring. METHODS: We retrospectively analyzed 50 IDH1/2-mutated AML/MDS-EB cases of our institution, to identify recurrent co-mutations, immunophenotypes, patterns of co-variance of IDH1/2 allele burdens with those of recurrent co-mutations, frequency of persistent IDH1/2 mutation as clonal hematopoiesis of indeterminate potential (CHIP) in remission and response to hypomethylating agents. RESULTS: Most frequently co-mutated genes were DNMT3A, SRSF2 and NPM1. Most cases with co-existent IDH1/2 and NPM1 mutations (11/13) showed an 'APL-like' immunophenotype (CD34-HLADR-). Allele burdens of mutated IDH1/2 were identical to mutated SRSF2 allele burdens at diagnosis and remission, but not always to mutated NPM1 allele burden in remission. We show persistence of significant mutIDH1/2 allele burden in approximately one-fourth of patients with deep remissions. IDH1/2 mutations were significantly more frequent among responders to first-line HMA-based regimens than among non-responders, in patients treated for myeloid neoplasms with excess blasts. CONCLUSIONS: IDH1/2 mutations are most frequently accompanied by DNMT3A, SRSF2 and NPM1 mutations. NPM1-IDH1/2 mutated AML has a mature phenotype possibly amenable to differentiation therapies. IDH1/2 and SRSF2 mutations probably arise at the same developmental stage of the disease, as their allele burdens covariate. IDH1/2 mutation represents CHIP in a substantial proportion of cases and is therefore no reliable residual disease marker. The preferential presence of IDH1/2 mutations among HMA-responders could inform therapeutic decisions if confirmed in larger series.

Prognostic significance of signal transducer and activator of transcription 5 and 5b expression in Epstein-Barr virus-positive patients with chronic lymphocytic leukemia.

Signal transducer and activator of transcription (STAT) proteins have been intensively studied in hematologic malignancies, and the efficacy of agents against STATs in lymphomas is already under research. We investigated the expression of total STAT5 and STAT5b in peripheral blood samples of patients with chronic lymphocytic leukemia (CLL) in correlation with the presence of Epstein-Barr Virus (EBV) and its major oncoprotein (latent membrane protein 1, LMP1). The EBV load was measured in the peripheral blood by real-time PCR for the BXLF1 gene and the levels of LMP1 by PCR and ELISA. Western blotting was performed for total STAT5 and STAT5b in protein extracts. STAT5b was only expressed in patients (not in healthy subjects) and STAT5 but particularly STAT5b expression was correlated with the presence of the virus (77.3% vs. 51.2%, P = 0.006 for STAT5b) and to the expression of LMP1 (58.3% vs. 21.6%, P = 0.011 for STAT5b). Moreover, the expression of STAT5b and the presence of EBV and LMP1 were strongly negatively correlated with the overall survival of the patients (log-rank test P = 0.011, 0.015, 0.006, respectively). Double positive (for EBV and STAT5b) patients had the lowest overall survival (log-rank test P = 0.013). This is the first report of a survival disadvantage of EBV+ patients with CLL, and the first time that STAT5b expression is correlated with survival. The correlation of STAT5 expression with the presence of the virus, along with our survival correlations defines a subgroup of patients with CLL that may benefit from anti-STAT agents.

Expression, prognostic significance and mutational analysis of protein tyrosine phosphatase SHP-1 in chronic myeloid leukemia.

The protein tyrosine phosphatase SHP-1 dephosphorylates BCR-ABL1, thereby serving as a potential control mechanism of BCR-ABL1 kinase activity. Pathways regulating SHP-1 expression, which could be exploited in the therapeutics of TKI-resistant chronic myeloid leukemia (CML), remain unknown. Moreover, the questions of whether there is any kind of SHP-1 deregulation in CML, contributing to disease initiation or evolution, as well as the question of prognostic significance of SHP-1, have not been definitively answered. This study shows moderately lower SHP-1 mRNA expression in chronic phase CML patients in comparison to healthy individuals and no change in SHP-1 mRNA levels after successful TKI treatment. Mutational analysis of the aminoterminal and phosphatase domains of SHP-1 in patients did not reveal genetic lesions. This study also found no correlation of SHP-1 expression at diagnosis with response to treatment, although a trend for lower SHP-1 expression was noted in the very small non-responders' group of the 3-month therapeutic milestone.

5-Azacytidine in the Treatment of Intermediate-2 and High-risk Myelodysplastic Syndromes and Acute Myeloid Leukemia. A Five-year Experience with 44 Consecutive Patients.

BACKGROUND/AIM: The hypomethylating agent 5-azacytidine has been the standard-of-care for patients with higher-risk myelodysplastic syndrome (MDS) during the past few years. Its efficacy has been proven in large clinical trials, and its safety has been shown to be superior to that of conventional treatments. PATIENTS AND METHODS: We conducted a retrospective study on the efficacy and safety of 5-azacytidine in 44 consecutive patients with MDS and acute myeloid leukemia treated with 5-azacytidine during a 63-month period. We recorded the clinical and laboratory characteristics of the patients and we analyzed the response to treatment, overall survival and adverse events during treatment. RESULTS: The median overall survival was 13 months, while serious adverse events consisted mostly of neutropenic infections. CONCLUSION: We reached two possibly valuable conclusions: Younger patients (<73 years), as well as patients receiving treatment at longer than 28-day intervals had a significantly higher overall survival.

Cytomegalovirus meningoencephalitis after rituximab treatment for primary central nervous system lymphoma.

The efficacy and safety of rituximab against B-cell lymphomas is well established. However, there has been an increased incidence of infectious complications after rituximab treatment, mostly hepatitis B reactivation and progressive multifocal leukoencephalopathy. This is the case of a 67-year-old patient with primary central nervous system lymphoma, who developed cytomegalovirus meningoencephalitis after receiving high-dose chemotherapy and rituximab. As there was no evidence of lymphoma relapse or additional immunosuppression, besides his previous treatment, an association between rituximab and cytomegalovirus meningoencephalitis cannot be ruled out.

An adult patient with systemic mastocytosis and B-acute lymphoblastic leukemia.

Mastocytosis is a myeloproliferative neoplasm characterized by clonal expansion of abnormal mast cells, ranging from the cutaneous forms of the disease to mast cell leukemia. In a significant proportion of patients, systemic mastocytosis (SM) coexists with another hematologic malignancy, termed systemic mastocytosis with an associated hematologic nonmast cell lineage disorder (SM-AHNMD). Despite the pronounced predominance of concomitant myeloid neoplasms, the much more unusual coexistence of lymphoproliferative diseases has also been reported. Imatinib mesylate (IM) has a role in the treatment of SM in the absence of the KITD816V mutation. In the setting of SM-AHNMD, eradicating the nonmast cell malignant clone greatly affects prognosis. We report a case of an adult patient with SM associated with B-lineage acute lymphoblastic leukemia (B-ALL). Three cases of concurrent adult ALL and mastocytosis have been reported in the literature, one concerning SM and two concerning cutaneous mastocytosis (CM), as well as six cases of concomitant CM and ALL in children.

PARP1-driven apoptosis in chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is considered a malignancy resulting from defects in apoptosis. For this reason, targeting apoptotic pathways in CLL may be valuable for its management. Poly [ADP-ribose] polymerase 1 (PARP1) is the main member of a family of nuclear enzymes that act as DNA damage sensors. Through binding on DNA damaged structures, PARP1 recruits repair enzymes and serves as a survival factor, but if the damage is severe enough, its action may lead the cell to apoptosis through caspase activation, or necrosis. We measured the PARP1 mRNA and protein pretreatment levels in 26 patients with CLL and the corresponding posttreatment levels in 15 patients after 3 cycles of immunochemotherapy, as well as in 15 healthy blood donors. No difference was found between the pre- and posttreatment levels of PARP1, but we found a statistically significant relative increase of the 89 kDa fragment of PARP1 that is cleaved by caspases in the posttreatment samples, indicating PARP1-related apoptosis in CLL patients after treatment. Our findings constitute an important step in the field, especially in the era of PARP1 inhibitors, and may serve as a base for future clinical trials with these agents in CLL.

Survivin messenger RNA levels in Epstein-Barr virus-positive patients with leukemic low-grade B-cell lymphomas expressing the latent membrane protein 1: evidence of apoptotic function?

BACKGROUND: Epstein-Barr virus (EBV) is a ubiquitous pathogen that chronically infects B lymphocytes and is implicated in the pathogenesis of lymphoproliferative diseases. Latent membrane protein 1 (LMP1), the major oncoprotein of the virus, has been shown to inhibit apoptosis and trigger survivin expression in malignant cell lines. LMP1 expression has been detected in patients with chronic lymphocytic leukemia, but its properties have not been studied in patients with low-grade B-cell lymphomas. Recent data show that LMP1 can simultaneously induce and inhibit apoptosis in B cells. We detected LMP1 messenger RNA (mRNA) in patients with leukemic low-grade B-cell lymphoma and correlated the expression of the antiapoptotic molecule survivin to that of LMP1 in this group of patients. PATIENTS AND METHODS: Peripheral whole blood from 64 patients with low-grade B-cell lymphoma was tested by quantitative reverse transcriptase-polymerase chain reaction (PCR) for the presence of the BXLF-1 gene of EBV, and positive samples were tested by conventional PCR for LMP1 expression. Accordingly, survivin mRNA levels were measured by quantitative reverse transcriptase PCR in all samples and compared between LMP1-positive (LMP1(+)) and LMP1(-) patients. RESULTS: The BXLF-1 gene was detected in 27 of 64 patients (42%). LMP1 was expressed in 22 of 27 (81%) EBV(+) patients. Survivin expression was found to be 6.36 times higher in LMP1(-) patients than in LMP1(+) patients (P = .008). CONCLUSION: Our results imply that in patients with non-EBV-related leukemic low-grade B-cell lymphoma, LMP1 expression is possibly correlated to apoptosis, as indicated by the lower survivin mRNA levels in LMP1(+) patients.

Systemic mastocytosis accompanied by a non-secretory plasma cell dyscrasia and nephrotic syndrome-level proteinuria in a 76-year-old patient.

We report here the interesting case of a 76-year-old man with severe proteinuria who was diagnosed with systemic mastocytosis accompanied by a clonal non-mast-cell lineage haematological disorder (a non-secretory plasma cell dyscrasia). This is a unique report of systemic mastocytosis with a non-secretory plasma cell dyscrasia and nephrotic syndrome. The pathophysiological relevance between these entities along with the probability of occult amyloidosis is discussed.

Evidence for regulation of oxidative stress by latent membrane protein 1 oncoprotein in patients with low-grade leukemic B cell lymphoma with latent Epstein-Barr virus infection.

The role of latent Epstein-Barr virus (EBV) infection in the pathogenesis of low-grade B cell non-Hodgkin lymphoma (B-NHL) has not been studied. We therefore investigated the incidence of latent EBV infection in a group of patients with leukemic low-grade B-NHL, as well as the incidence of viral latent membrane protein 1 (LMP1) oncoprotein expression in the same patient group. Furthermore, in an attempt to elucidate the role of this viral oncoprotein in non-EBV-related lymphomas, we correlated the expression of LMP1 with the level of oxidative stress, a parameter related to apoptosis. In the present study we detected lower levels of oxidative stress in the sera of LMP1-positive patients. This possibly implies an anti-apoptotic role of this viral oncoprotein in low-grade B cell lymphomas. However, LMP1 expression status did not affect expression of the major anti-apoptotic gene BCL-2.

Rituximab in the treatment of EBV-positive low grade B-cell lymphoma.

BACKGROUND: Following infection of B lymphocytes by Epstein Barr virus (EBV), the viral genome remains in the nucleus, and a latency phase is established, during which only a small proportion of the viral genes are expressed. Among them, LMP1 is essential for transformation. Rituximab is a potent agent used in the treatment of low grade B-cell lymphomas and is also widely used for the treatment of post-transplant lymphoproliferative disorders caused by EBV. The effect of rituximab treatment on the latent EBV infection in non-transplant patients with lymphoproliferative disorders has never been studied to our knowledge. PATIENTS AND METHODS: We studied, the effect of rituximab-based immunochemotherapy on the EBV status of 44 patients with leukemic low grade B-cell lymphoma. RESULTS: After three cycles of rituximab-based treatment, only 1/17 patients was still positive for EBV. DISCUSSION: Our results suggest that rituximab used in the treatment of EBV-positive low-grade lymphoma is efficient in eradicating the virus from the peripheral blood, a fact with potential implications in the course and prognosis of the disease.

Cessation of tyrosine kinase inhibitors in patients with chronic-phase chronic myelogenous leukemia following durable complete molecular response: a single center facing the dilemma.

Tyrosine kinase inhibitors (TKIs), namely imatinib mesylate (IM) and recently approved second-generation TKIs dasatinib and nilotinib, are currently considered the treatment of choice for newly-diagnosed chronic phase chronic myelogenous leukemia (CP-CML). Although treatment with TKIs has not yet been proven curative, it certainly accomplishes a sustained control of the disease in the vast majority of patients. More than a decade after the successful launching of IM in first-line treatment of CP-CML and the subsequent introduction of second-generation TKIs in this setting, the question of the possibility of TKI cessation in a specific subset of patients has emerged. Side-effects of TKIs, along with some patients' wish to abandon the drugs and the rising financial burden upon healthcare systems, have led to the dilemma whether IM can be safely withdrawn after achieving deep molecular remissions and which patients are suitable for this discontinuation. We examined the data of our patients with CML in search of potential canditates for cessation of TKI therapy and identified their characteristics. We also performed a thorough review of the relevant literature. Eight out of fifty patients were discriminated on grounds of sustained complete molecular response (CMR) exceeding 12 months, most of them with a low or intermediate Sokal score at diagnosis. The median interval from IM initiation to CMR was almost 2 years and the median duration of detected CMR reached 6.5 years. Based on the promising results of prospective clinical trials reporting successful cessation of treatment with TKIs on selected subgroups of patients, we decided to proceed to interruption of therapy in the specific subset of our patients and closely monitor their response.

STAT6-mediated BCL6 repression in primary mediastinal B-cell lymphoma (PMBL).

Primary mediastinal B-cell lymphoma (PMBL) is characterized by aberrant activation of JAK/STAT-signaling resulting in constitutive presence of phosphorylated STAT6 (pSTAT6). In primary PMBL samples pSTAT6 is only expressed in a sub-population of lymphoma cells in a pattern that is reminiscent of that of the BCL6 oncogene. Double-fluorescence staining was carried out to determine the association between these two proteins in ten primary PMBL cases and three available PMBL cell line models. Surprisingly, only a minute fraction of double-positive nuclei was observed, while each sample contained considerable fractions of single-positive pSTAT6 and BCL6 nuclei. The intratumoral coexistence of BCL6+/pSTAT6- and BCL6-/pSTAT6+ subpopulations suggests a negative interaction between these factors. In silico screening of the STAT6 /BCL6 promoters for DNA consensus binding sites identified five STAT-binding-sites in the BCL6 promoter. We confirmed STAT6 binding to the BCL6 promoter in vitro and in vivo by band shift / super shift assays and chromatin immunoprecipitations. Using BCL6 luciferase reporter assays, depletion of STAT6 by siRNA, and ectopic overexpression of a constitutive active STAT6 mutant, we proved that pSTAT6 is sufficient to transcriptionally repress BCL6. Recently developed small molecule inhibitors 79-6 and TG101348 that increases BCL6 target gene expression and decreases pSTAT6 levels, respectively, demonstrate that a combined targeting results in additive efficacy regarding their negative effect on cell viability. The delineated pSTAT6-mediated molecular repression mechanism links JAK/STAT to BCL6-signaling in PMBL and may carry therapeutic potential.

POZ-, AT-hook-, and zinc finger-containing protein (PATZ) interacts with human oncogene B cell lymphoma 6 (BCL6) and is required for its negative autoregulation.

The PATZ1 gene encoding a POZ/AT-hook/Kruppel zinc finger (PATZ) transcription factor, is considered a cancer-related gene because of its loss or misexpression in human neoplasias. As for other POZ/domain and Kruppel zinc finger (POK) family members, the transcriptional activity of PATZ is due to the POZ-mediated oligomer formation, suggesting that it might be not a typical transactivator but an architectural transcription factor, thus functioning either as activator or as repressor depending on the presence of proteins able to interact with it. Therefore, to better elucidate PATZ function, we searched for its molecular partners. By yeast two-hybrid screenings, we found a specific interaction between PATZ and BCL6, a human oncogene that plays a key role in germinal center (GC) derived neoplasias. We demonstrate that PATZ and BCL6 interact in germinal center-derived B lymphoma cells, through the POZ domain of PATZ. Moreover, we show that PATZ is able to bind the BCL6 regulatory region, where BCL6 itself acts as a negative regulator, and to contribute to negatively modulate its activity. Consistently, disruption of one or both Patz1 alleles in mice causes focal expansion of thymus B cells, in which BCL6 is up-regulated. This phenotype was almost completely rescued by crossing Patz1(+/-) with Bcl6(+/-) mice, indicating a key role for Bcl6 expression in its development. Finally, a significant number of Patz1 knock-out mice (both heterozygous and homozygous) also develop BCL6-expressing lymphomas. Therefore, the disruption of one or both Patz1 alleles may favor lymphomagenesis by activating the BCL6 pathway.

ZEB1 and CtBP form a repressive complex at a distal promoter element of the BCL6 locus.

BCL6 is essential for normal antibody responses and is highly expressed in germinal centre B-cells. Constitutive expression due to chromosomal translocations or mutations of cis-acting regulatory elements contributes to diffuse large B-cell lymphoma. BCL6 expression is therefore tightly regulated in a lineage- and developmental-stage-specific manner, and disruption of normal controls can contribute to lymphomagenesis. In order to discover potential cis-acting control regions we carried out DNase I-hypersensitive site mapping. Gel-shift assays and chromatin immunoprecipitation of the core region of a hypersensitive site 4.4 kb upstream of BCL6 transcription initiation (HSS-4.4) showed an E-box element-binding ZEB1 (zinc finger E-boxbinding homeobox 1) and the co-repressor CtBP (C-terminal binding protein). As compared with peripheral blood B-cells, ZEB1, a two-handed zinc finger transcriptional repressor, is expressed at relatively low levels in germinal centre cells, whereas BCL6 has the opposite pattern of expression. Transfection of ZEB1 cDNA caused a reduction in BCL6 expression and a mutated ZEB1, incapable of binding CtBP, lacked this effect. siRNA (small interfering RNA)-mediated knockdown of ZEB1 or CtBP produced an increase in BCL6 mRNA. We propose that HSS-4.4 is a distal promoter element binding a repressive complex consisting of ZEB1 and CtBP. CtBP is ubiquitously expressed and the results of the present study suggest that regulation of ZEB1 is required for control of BCL6 expression.