miR-1202 acts as anti-oncomiR in myeloid leukaemia by down-modulating GATA-1S expression

Transient abnormal myelopoiesis (TAM) is a Down syndrome-related pre-leukaemic condition characterized by somatic mutations in the haematopoietic transcription factor GATA-1 that result in exclusive production of its shorter isoform (GATA-1S). Given the common hallmark of altered miRNA expression profiles in haematological malignancies and the pro-leukaemic role of GATA-1S, we aimed to search for miRNAs potentially able to modulate the expression of GATA-1 isoforms. Starting from an in silico prediction of miRNA binding sites in the GATA-1 transcript, miR-1202 came into our sight as potential regulator of GATA-1 expression. Expression studies in K562 cells revealed that miR-1202 directly targets GATA-1, negatively regulates its expression, impairs GATA-1S production, reduces cell proliferation, and increases apoptosis sensitivity. Furthermore, data from TAM and myeloid leukaemia patients provided substantial support to our study by showing that miR-1202 down-modulation is accompanied by increased GATA-1 levels, with more marked effects on GATA-1S. These findings indicate that miR-1202 acts as an anti-oncomiR in myeloid cells and may impact leukaemogenesis at least in part by down-modulating GATA-1S levels.

Granulocyte transfusion during cord blood transplant for relapsed, refractory AML is associated with massive CD8+ T-cell expansion, significant cytokine release syndrome and induction of disease remission

In high-risk myeloid malignancy, relapse is reduced using cord blood transplant (CBT) but remains the principal cause of treatment failure. We previously described T-cell expansion in CBT recipients receiving granulocyte transfusions. We now report the safety and tolerability of such transfusions, T-cell expansion data, immunophenotype, cytokine profiles and clinical response in children with post-transplant relapsed acute leukaemia who received T-replete, HLA-mismatched CBT and pooled granulocytes within a phase I/II trial (ClinicalTrials.Gov NCT05425043). All patients received the transfusion schedule without significant clinical toxicity. Nine of ten patients treated had detectable measurable residual disease (MRD) pre-transplant. Nine patients achieved haematological remission, and eight became MRD negative. There were five deaths: transplant complications (n = 2), disease (n = 3), including two late relapses. Five patients are alive and in remission with 12.7 months median follow up. Significant T-cell expansion occurred in nine patients with a greater median lymphocyte count than a historical cohort between days 7-13 (median 1.73 × 109 /L vs. 0.1 × 109 /L; p < 0.0001). Expanded T-cells were predominantly CD8+ and effector memory or TEMRA phenotype. They exhibited markers of activation and cytotoxicity with interferon-gamma production. All patients developed grade 1-3 cytokine release syndrome (CRS) with elevated serum IL-6 and interferon-gamma.

[First Hungarian report of Geotrichum capitatum/Saprochaete capitata infection in an immunocompromised child]

Patients with leukemia may occasionally suffer from rare opportunistic fungal infections with poor prognosis. Fungal infection caused by Geotrichum captitatum has not yet been described in Hungary. With this case report, we would like to draw attention to the fungal infection caused by G. capitatum. The 1.5-year-old girl with acute myeloid leukemia was treated for relapse diagnosed +120 days after a sibling donor bone marrow transplantation. High-grade, fluctuating fever began 11 days after the start of chemotherapy which did not decrease despite combined treatment with broad-spectrum antibiotics and antifungals (posaconasole). Due to worsening respiratory symptoms, a chest CT-scan was performed, raising suspicion of an invasive fungal infection. Blood culture confirmed G. capitatum infection. Initial empiric treatment with liposomal amphotericin B was combined with voriconazole based on international experience. However, we did not observe any improvement, and a few days later the patient passed away due to progression of the underlying disease. G. capitatum (presently known as Saprochaete capitata) is an ubiquitous yeast that can cause an infection with a poor prognosis, mainly in patients with leukemia. Its symptoms primarily appear in the skin and respiratory tract. The accurate identification of this pathogen is essential because the standard diagnostic tests do not give a specific reaction. Based on the limited international experience, the combination of amphotericin B and voriconazole can play a fundamental role in the treatment, however, even with adequate therapy 50% of the cases are fatal. By describing the first Hungarian case caused by G. capitatum, we draw attention to the importance of this rare, opportunistic fungal species with a poor prognosis that develops in immunosuppressed patients. Orv Hetil. 2023; 164(26): 1034-1038.

Development and validation of a prognostic scoring model to risk stratify childhood acute myeloid leukaemia

To create a personal prognostic model and modify the risk stratification of paediatric acute myeloid leukaemia, we downloaded the clinical data of 597 patients from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database as a training set and included 189 patients from our centre as a validation set. In the training set, age at diagnosis, -7/del(7q) or -5/del(5q), core binding factor fusion genes, FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD)/nucleophosmin 1 (NPM1) status, Wilms tumour 1 (WT1) mutation, biallelic CCAAT enhancer binding protein alpha (CEBPA) mutation were strongly correlated with overall survival and included to construct the model. The prognostic model demonstrated excellent discriminative ability with the Harrell's concordance index of 0.68, 3- and 5-year area under the receiver operating characteristic curve of 0.71 and 0.72 respectively. The model was validated in the validation set and outperformed existing prognostic systems. Additionally, patients were stratified into three risk groups (low, intermediate and high risk) with significantly distinct prognosis, and the model successfully identified candidates for haematopoietic stem cell transplantation. The newly developed prognostic model showed robust ability and utility in survival prediction and risk stratification, which could be helpful in modifying treatment selection in clinical routine.

A nonrandomized phase I and biomarker trial of regorafenib in advanced myeloid malignancies

We conducted a single-center, open-label, dose escalation, and expansion phase I trial of the antiangiogenic multikinase inhibitor regorafenib in patients with advanced myeloid neoplasms. We enrolled 16 patients with relapsed/refractory acute myeloid leukemia (AML), myeloproliferative neoplasms (MPN), chronic myelomonocytic leukemia (CMML), or myelodysplastic syndrome (MDS). A 3 + 3 dose escalation design was used with two planned dose levels (120 or 160 mg daily) and one de-escalation level (80 mg daily). An additional 10 patients were treated on an expansion cohort. The recommended phase two dose of regorafenib was 160 mg daily, with no dose-limiting toxicities. The best overall disease response by International Working Group criteria included one partial and stable disease in 11 patients. Tissue studies indicated no change in Ras/mitogen-activated protein kinase (MAPK) pathway activation in responders. Pharmacodynamic changes in plasma VEGF, PlGF, and sVEGFR2 were detected during treatment. Baseline proinflammatory and angiogenic cytokine levels were not associated with clinical response. Single-agent regorafenib demonstrated an acceptable safety profile in relapsed/refractory myeloid malignancy patients. Most patients achieved stable disease, with modest improvements in cell counts in some MDS patients. Biomarker studies were consistent with on-target effects of regorafenib on angiogenesis. Future studies should investigate the role of regorafenib in combination therapy approaches.

Therapy-related myeloid neoplasms with normal karyotype show distinct genomic and clinical characteristics compared to their counterparts with abnormal karyotype

Therapy-related myeloid neoplasms (t-MNs) are a complication of treatment with cytotoxic chemotherapy and/or radiation therapy. The majority of t-MNs show chromosomal abnormalities associated with myelodysplastic syndrome (MDS) or KMT2A rearrangements and are characterized by poor clinical outcomes. A small but substantial subset of patients have normal karyotype (NK) and their clinical characteristics and mutational profiles are not well studied. We retrospectively studied patients diagnosed with t-MN at three institutions and compared the mutational profile and survival data between t-MNs with NK and t-MNs with abnormal karyotype (AK). A total of 204 patients with t-MN were identified including 158 with AK and 46 with NK. NK t-MNs, compared to AK, were enriched for mutations in TET2 (p < 0.0001), NPM1 (p < 0.0001), ASXL1 (p = 0.0003), SRSF2 (p < 0.0001), RUNX1 (p = 0.0336) and STAG2 (p = 0.0099) and showed a significantly lower frequency of TP53 mutations (p < 0.0001). Overall survival (OS) was significantly lower in AK t-MNs as compared to NK cases (p = 0.0094). In our study, NK t-MNs showed a significantly better OS, a higher prevalence of MN-associated mutations and a lower frequency of TP53 mutations compared to their AK counterparts. The distinct clinical and mutational profile of NK t-MNs merits a separate classification.

A novel algorithmic approach to generate consensus treatment guidelines in adult acute myeloid leukaemia

Induction therapy for acute myeloid leukaemia (AML) has changed with the approval of a number of new agents. Clinical guidelines can struggle to keep pace with an evolving treatment and evidence landscape and therefore identifying the most appropriate front-line treatment is challenging for clinicians. Here, we combined drug eligibility criteria and genetic risk stratification into a digital format, allowing the full range of possible treatment eligibility scenarios to be defined. Using exemplar cases representing each of the 22 identified scenarios, we sought to generate consensus on treatment choice from a panel of nine aUK AML experts. We then analysed >2500 real-world cases using the same algorithm, confirming the existence of 21/22 of these scenarios and demonstrating that our novel approach could generate a consensus AML induction treatment in 98% of cases. Our approach, driven by the use of decision trees, is an efficient way to develop consensus guidance rapidly and could be applied to other disease areas. It has the potential to be updated frequently to capture changes in eligibility criteria, novel therapies and emerging trial data. An interactive digital version of the consensus guideline is available.

The Mutational Landscape of Myeloid Leukaemia in Down Syndrome

Children with Down syndrome (DS) are particularly prone to haematopoietic disorders. Paediatric myeloid malignancies in DS occur at an unusually high frequency and generally follow a well-defined stepwise clinical evolution. First, the acquisition of mutations in the GATA1 transcription factor gives rise to a transient myeloproliferative disorder (TMD) in DS newborns. While this condition spontaneously resolves in most cases, some clones can acquire additional mutations, which trigger myeloid leukaemia of Down syndrome (ML-DS). These secondary mutations are predominantly found in chromatin and epigenetic regulators-such as cohesin, CTCF or EZH2-and in signalling mediators of the JAK/STAT and RAS pathways. Most of them are also found in non-DS myeloid malignancies, albeit at extremely different frequencies. Intriguingly, mutations in proteins involved in the three-dimensional organization of the genome are found in nearly 50% of cases. How the resulting mutant proteins cooperate with trisomy 21 and mutant GATA1 to promote ML-DS is not fully understood. In this review, we summarize and discuss current knowledge about the sequential acquisition of genomic alterations in ML-DS.

An open-source, expert-designed decision tree application to support accurate diagnosis of myeloid malignancies

Accurate, reproducible diagnoses can be difficult to make in haemato-oncology due to multi-parameter clinical data, complex diagnostic criteria and time-pressured environments. We have designed a decision tree application (DTA) that reflects WHO diagnostic criteria to support accurate diagnoses of myeloid malignancies. The DTA returned the correct diagnoses in 94% of clinical cases tested. The DTA maintained a high level of accuracy in a second validation using artificially generated clinical cases. Optimisations have been made to the DTA based on the validations, and the revised version is now publicly available for use at http://bit.do/ADAtool.

Is the risk of childhood leukaemia associated with socioeconomic measures in Denmark? A nationwide register-based case-control study

The aetiology of childhood leukaemia is poorly understood. Knowledge about differences in risk by socioeconomic status (SES) may enhance etiologic insights. We conducted a nationwide register-based case-control study to evaluate socioeconomic differences in the risk of childhood leukaemia in Denmark and to access whether associations varied by different measures of SES, time point of assessment, leukaemia type and age at diagnosis. We identified all cases of leukaemia in children aged 0 to 19 years, born and diagnosed between 1980 and 2013 from the Danish Cancer Registry (N = 1336) and sampled four individually matched controls per case (N = 5330). We used conditional logistic regression models for analysis. Medium and high level of parental education was associated with a higher risk of acute myeloid leukaemia (AML) in the offspring, mainly driven by children diagnosed at ages 0 to 4 years [odds ratio (OR) for high maternal education = 3.07; 95% confidence interval (CI): 1.44-6.55]. We also observed a modestly increased risk for lymphoid leukaemia (LL) in association with higher level of parental education, but only in children diagnosed at ages 5 to 19 years. Higher parental income was associated with an increased risk of LL but not AML among children aged 5 to 19 years at diagnosis (OR for high maternal income = 2.78; 95% CI: 1.32-5.89). Results for neighbourhood SES measures indicated null associations. Bias or under-ascertainment of cases among families with low income or basic education are unlikely to explain the observed socioeconomic differences. Future research addressing explicitly the underlying mechanisms of our results may help to enhance etiologic insights of the disease.

How to address second and therapy-related acute myelogenous leukaemia

Secondary acute myelogenous leukaemia (AML), as compared to de novo AML, occurs in the more elderly population, is independently more resistant to cytotoxic chemotherapy, has a higher relapse rate, and a worse prognosis. Secondary AML (sAML) is a heterogeneous disease, both biologically and clinically, even within the World Health Organization subgroups of sAML. Outcomes are the poorest in subgroups with sAML arising from an antecedent haematologic disorder which has been previously treated (ts-AML), and sAML in patients <55 years of age. This review describes the suboptimal outcomes of contemporary therapy, to support the notion of an unmet need for innovative treatment strategies in sAML. Despite the recent approval of CPX-351, long-term outcomes for this high-risk disease remain dismal. Resistance mechanisms to intensive chemotherapy contribute to relapse. Targeted immune therapy may avoid multidrug resistance mechanisms, but are unlikely to provide long-term remission due to a complex and rapidly evolving clonal disease profile. Advances for sAML will likely be accomplished by CAR T cell therapy or bispecific antibodies providing a bridge to allogeneic stem cell transplantation. Therefore, focus should be placed on novel strategies that can augment the untargeted effector function of allogeneic grafts.

Peripheral blood blast rate of clearance is an independent predictor of clinical response and outcomes in acute myeloid leukaemia

The day 14 bone marrow aspirate and biopsy (D14BM) is regularly used to predict achievement of complete remission (CR) with induction chemotherapy in acute myeloid leukemia (AML), however its utility has been questioned. Clearance of peripheral blood blasts (PBB) may serve as an early measure of chemosensitivity. PBB rate of clearance (PBB-RC) was calculated for treatment-naive AML patients (n = 164) undergoing induction with an anthracycline and cytarabine (7+3) and with detectable PBB at diagnosis. PBB-RC was defined as the percentage of the absolute PBB count on the day of diagnosis that was cleared with each day of therapy, on average, until D14 or day of PBB clearance. Each 5% increase in PBB-RC approximately doubled the likelihood of D14BM clearance (OR = 1·81; 95% CI: 1·24-2·64, P < 0·005). PBB-RC was also associated with improved CR rates (OR per 5% = 1·97; 95% CI: 1·27-3·01, P < 0·005) and overall survival (OS) [hazard ratio (HR) per 5% = 0·67; 95% CI: 0·52-0·87]. African American patients had poorer OS adjusted for PBB-RC (HR = 2·18; 95% CI: 1·13-4·23), while race was not associated with D14BM or CR rate. PBB-RC during induction chemotherapy is predictive of D14BM clearance, CR, and OS, and can therefore serve as a prognostic marker for clinical outcomes in AML.

Next-generation sequencing for measurable residual disease detection in acute myeloid leukaemia

Acute myeloid leukaemia (AML) is a blood cancer characterized by acquired genetic mutations. There is great interest in accurately establishing measurable residual disease (MRD) burden in AML patients in remission after treatment but at risk of relapse. However, inter- and intrapatient genetic diversity means that, unlike in the chronic myeloid and acute promyelocytic leukaemias, no single genetic abnormality is pathognomonic for all cases of AML MRD. Next-generation sequencing offers the opportunity to test broadly and deeply for potential genetic evidence of residual AML, and while not currently accepted for such use clinically, is likely to be increasingly used for AML MRD testing in the future.

Patients aged less than 3 years with acute myeloid leukaemia characterize a molecularly and clinically distinct subgroup

Although infants (age <1 year) with acute myeloid leukaemia (AML) have unique characteristics and are vulnerable to chemotherapy, children aged 1-2 years with AML may have characteristics similar to that of infants. Thus, we analysed 723 paediatric AML patients treated on the Japanese AML99 and AML-05 trials to identify characteristics of younger children. We identified patients aged <3 years (the younger group) as a distinct subgroup. KMT2A-rearrangement (KMT2A-R), CBFA2T3-GLIS2, CBFB-MYH11 and NUP98-KDM5A were frequently found in the younger group. Prognostic analyses revealed poor 5-year overall survival (OS), event-free survival (EFS) and cumulative incidence of relapse (CIR) in patients with CBFA2T3-GLIS2 (42%, 17% and 83%, respectively) and those with NUP98-KDM5A (33%, 17% and 83%, respectively). Additionally, we identified KMT2A-R and CBFB-MYH11 as age-specific prognostic markers. Regarding KMT2A-R, the younger group had significantly better OS, EFS and CIR than the older group (aged 3 to <18 years) (P = 0·023, 0·011 and <0·001, respectively). Conversely, concerning CBFB-MYH11, the younger group had significantly poor EFS and CIR than the older group (each P < 0·001), suggesting that certain molecular markers are linked to different prognoses according to age. Therefore, we characterized patients <3 years as a distinct subgroup of paediatric AML.

Anthropometric factors and risk of myeloid leukaemias and myelodysplastic syndromes: a prospective study and meta-analysis

There is insufficient evidence linking excess body weight to risk of myeloid malignancies. We investigated this association using data from the Cancer Prevention Study-II (CPS-II), and a meta-analysis of published cohort studies. Among 152 090 CPS-II participants, 387 acute myeloid leukaemias (AML), 100 chronic myeloid leukaemias (CML) and 170 MDS were identified over 21 years of follow-up. In CPS-II, body mass index (BMI) was weakly associated with risk of CML (hazard ratio [HR] = 1·04, 95% confidence interval [CI]: 0·99-1·09 per 1 unit increase in BMI), AML (HR = 1·01, 95% CI: 0·98-1·03) and MDS (HR = 1·03, 95% CI: 0·99-1·07). After controlling for other anthropometric factors, no clear association was observed for height, BMI at age 18 years or weight change. In the meta-analysis (n = 7117 myeloid leukaemias), BMI 25-29·9 kg/m² (HR_pooled  = 1·36, 95% CI: 1·12-1·59) and BMI ≥30 kg/m² (HR_pooled  = 1·43, 95% CI: 1·18-1·69) were associated with higher risk of myeloid leukaemia overall, compared to a BMI <25 kg/m² . Likewise, BMI ≥25 kg/m² was positively associated with both AML and CML risk individually in the meta-analysis. These results underscore the need for large studies to detect associations with rare cancers, and show a modest, but positive association between excess body weight and myeloid malignancy risk.

Expression of functional neuronal receptor latrophilin 1 in human acute myeloid leukaemia cells

Acute myeloid leukaemia (AML) is a blood cancer affecting cells of myeloid lineage. It is characterised by rapid growth of malignant leukocytes that accumulate in the bone marrow and suppress normal haematopoiesis. This systemic disease remains a serious medical burden worldwide. Characterisation of protein antigens specifically expressed by malignant cells, but not by healthy leukocytes, is vital for the diagnostics and targeted treatment of AML. Here we report, for the first time, that the neuronal receptor latrophilin-1 is expressed in human monocytic leukaemia cell lines and in primary human AML cells. However, it is absent in healthy leukocytes. Latrophilin-1 is functional in leukaemia cells tested, and its biosynthesis is controlled through the mammalian target of rapamycin (mTOR), a master regulator of myeloid cell translational pathways. Our findings demonstrate that latrophilin-1 could be considered as a novel biomarker of human AML, which offers potential new avenues for AML diagnosis and treatment.

A retrospective review of acute myeloid leukaemia in 35 dogs diagnosed by a combination of morphologic findings, flow cytometric immunophenotyping and cytochemical staining results (2007-2015)

Acute myeloid leukaemia (AML) is an uncommon, rapidly progressive neoplasm in dogs. The aim of this retrospective study was to characterize the clinical presentation, haematologic findings, diagnostic imaging results, treatment and survival time of a contemporary cohort of dogs with AML. Diagnosis was based on >20% blasts in bone marrow or blood identified as myeloid based on morphologic findings, flow cytometric immunophenotyping and cytochemical staining. Medical records of 35 dogs diagnosed with AML from 2007 to 2015 were included. Most dogs presented with inappetence (66%) and lethargy (57%) and physical examination findings of peripheral lymphadenopathy (74%) and tachypnea (62%). Common haematologic findings were quantifiable circulating blasts (85%; median blast count 35 700/μL; range: 300-276 500/μL), anaemia (median haematocrit 34%; range: 11%-52%) and thrombocytopenia (median 57 000/μL; range: 9000-252 000/μL). Bicytopenia and pancytopenia were each found in 44% of dogs. Follow-up information was available for 34 dogs. The overall median survival time from diagnosis was 19 days (range: 1-121 days). Clinical progression in some dogs was not as rapid as previously reported. Haematologic responses to various chemotherapeutics were documented in 3 dogs, with associated survival times of 62, 103 and 121 days. Dogs treated with prednisone or a combination of chemotherapy and prednisone had improved survival compared to dogs that received symptomatic care only (P < .0001). Our results show canine AML has an overlapping clinical presentation with lymphoma. The prognosis for canine AML remains extremely guarded. Further studies are needed to optimize therapeutic regimens for dogs with AML.

Pattern Of Leukaemia Patients Admitted In Ayub Teaching Hospital Abbottabad

BACKGROUND

Any tissue of the body can give rise to cancer. However, those tissues which multiply rapidly are at high risk of developing cancer and haematopoietic system is one of them. Neoplasms of this system are known as leukaemia and lymphoma, according to the types of white cells involved. Study of cancer patterns in different societies, however can contribute a substantial knowledge about the aetiology of cancer. The present Study was designed and aimed to estimate the frequency of different types of leukaemia in patients admitted in Ayub Teaching hospital Abbottabad.

METHODS

Data from the patients admitted at oncology Department of Ayub Teaching Hospital Abbottabad from 2010 to 2015 was collected and analysed to calculate cumulative and year-wise frequency of leukaemia and its major types. Frequency distribution with reference to gender and age was also calculated.

RESULTS

In our analysis about 16% patients had acute myelocytic leukaemia and 32% patients had acute lymphocytic leukaemia; while chronic myeloid leukaemia outnumbered chronic lymphocytic leukaemia (11% and 3%); Hodgkin lymphoma was seen in 18% cases while Non Hodgkin lymphoma (NHL) was present in 20% cases. Out of the total, 150 cases (75%) belonged to mountainous areas of Hazara, i.e., 40 cases belonged to Kohistan, another 40 cases were residents of Battagram, 45 cases belonged to hilly areas of Mansehra and 25 cases to Kaghan valley, while only 50 (25%) cases were from the plain areas of Abbottabad and Haripur districts, i.e., 20 and 30 cases respectively.

CONCLUSIONS

Leukaemia is more common in hilly areas of Hazara, since majority of the cases belonged to well-known mountainous regions of Kohistan, Battagram, Kaghan or Mansehra and only few cases belonged to the plain areas of Abbottabad and Haripur districts.

Stromal CYR61 Confers Resistance to Mitoxantrone via Spleen Tyrosine Kinase Activation in Human Acute Myeloid Leukaemia

Approximately 50% of children with acute myeloid leukaemia (AML) relapse, despite aggressive chemotherapy. The bone marrow stromal environment protects leukaemia cells from chemotherapy (i.e., stroma-induced chemoresistance), eventually leading to recurrence. Our goal is to delineate the mechanisms underlying stroma-mediated chemoresistance in AML. We used two human bone marrow stromal cell lines, HS-5 and HS-27A, which are equally effective in protecting AML cells from chemotherapy-induced apoptosis in AML-stromal co-cultures. We found that CYR61 was highly expressed by stromal cells, and was upregulated in AML cells by both stromal cell lines. CYR61 is a secreted matricellular protein and is associated with cell-intrinsic chemoresistance in other malignancies. Here, we show that blocking stromal CYR61 activity, by neutralization or RNAi, increased mitoxantrone-induced apoptosis in AML cells in AML-stromal co-cultures, providing functional evidence for its role in stroma-mediated chemoresistance. Further, we found that spleen tyrosine kinase (SYK) mediates CYR61 signalling. Exposure to stroma increased SYK expression and activation in AML cells, and this increase required CYR61. SYK inhibition reduced stroma-dependent mitoxantrone resistance in the presence of CYR61, but not in its absence. Therefore, SYK is downstream of CYR61 and contributes to CYR61-mediated mitoxantrone resistance. The CYR61-SYK pathway represents a potential target for reducing stroma-induced chemoresistance.

Targeting of the Hedgehog pathway in myeloid malignancies: still a worthy chase?

Deregulated Hedgehog (Hh) signalling activity may be associated with a broad range of cancer types and hence has become an attractive target for therapeutic intervention. Although initial haematological interest focused on the therapeutic targeting of this pathway in chronic myeloid leukaemia), small molecule inhibitors targeting the Hh pathway are now being tested in a range of other myeloid disorders, including myelofibrosis, myelodysplasia and acute myeloid leukaemia. In this review we will evaluate the rationale for targeting of the Hh pathway in myeloid diseases and discuss the novel agents that have entered the clinical arena. We will discuss pre-clinical models, emerging clinical trial data, and suggest how these targeted therapies may address current unmet medical needs. Finally, we will explore potential limitations of these therapies due to the emergence of secondary resistance mechanisms and speculate on future developments within this arena.

The spectrum of somatic mutations in high-risk acute myeloid leukaemia with -7/del(7q)

-7/del(7q) occurs in half of myeloid malignancies with adverse-risk cytogenetic features and is associated with poor survival. We identified the spectrum of mutations that co-occur with -7/del(7q) in 40 patients with de novo or therapy-related myeloid neoplasms. -7/del(7q) leukaemias have a distinct mutational profile characterized by low frequencies of alterations in genes encoding transcription factors, cohesin and DNA-methylation-related proteins. In contrast, RAS pathway activating mutations occurred in 50% of cases, a significantly higher frequency than other acute myeloid leukaemias and higher than previously reported. Our data provide guidance for which pathways may be most relevant in the treatment of adverse-risk myeloid leukaemia.

Invasive fungal infection of the central nervous system in a patient with acute myeloid leukaemia

Background:

Although the new intensive chemotherapeutic programs introduced recently into hematooncological therapies have led to a higher number of recoveries, persistent neutropenia favours the spread of severe infections, frequently fungal infections. Systemic fungal infections in patients treated for proliferative diseases of the hematopoietic system are characterised by a severe, progressing course and high morbidity.

Case Reports:

We present a case report that demonstrates the diagnostic problem of lesions in the central nervous system which developed following the fourth block of chemotherapy in an eight-year-old boy treated for acute myeloid leukaemia. The risk factors, high values of the inflammatory parameters and imaging results enabled us to diagnose a fungal infection of the central nervous system.

Results:

A fast improvement in the clinical condition of the patient after the applied antifungal therapy and the regression of lesions in the central nervous system shown in the imaging studies confirmed our final diagnosis.

Immunotherapy of myeloid leukaemia

The treatment of myeloid leukaemia has progressed in recent years with the advent of donor leukocyte infusions (DLI), haemopoietic stem cell transplants (HSCTs) and targeted therapies. However, relapse has a high associated morbidity rate and a method for removing diseased cells in first remission, when a minimal residual disease state is achieved and tumour load is low, has the potential to extend remission times and prevent relapse especially when used in combination with conventional treatments. Acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS) are heterogeneous diseases which lack one common molecular target while chronic myeloid leukaemia (CML) patients have experienced prolonged remissions through the use of targeted therapies which remove BCR-ABL(+) cells effectively in early chronic phase. However, escape mutants have arisen and this therapy has little effectivity in the late chronic phase. Here we review the immune therapies which are close to or in clinical trials for the myeloid leukaemias and describe their potential advantages and disadvantages.

Maxillo-ethmoidal chloroma in acute myeloid leukaemia: case report

Chloroma, also called Granulocytic Sarcoma or Myeloid Sarcoma, is a rare malignant extra-medullary neoplasm of myeloid precursor cells. It is usually associated with myelo-proliferative disorders but its appearance may precede the onset of leukaemia. Chloroma may be found in several extracranial sites. Involvement of the head and neck region is uncommon. Differential diagnosis is often difficult and includes acute lymphoblastic leukaemia, large cell NHL, lymphoblastic lymphoma and Ewing's sarcoma. The case is presented of a maxillo-ethmoidal chloroma occurring in a case of poor prognosis acute myeloid leukaemia, emphasizing the clinical and cyto-histological features and problems concerning differential diagnosis.

Extramedullary myeloid cell tumours localised to the mediastinum: a rare clinicopathological entity with unique karyotypic features

Extramedullary myeloid cell tumour (EMMT) localised to the mediastinum is a rare manifestation of acute myeloid leukaemia, forming less than 4% of all cases of EMMT. In contrast to other types of EMMT, cytogenetic characteristics of this rare entity are relatively unknown. This report describes a patient with EMMT who had evidence of superior vena cava syndrome and normal peripheral blood counts at diagnosis. The results from an initial biopsy specimen were consistent with a diagnosis of mediastinal large B cell lymphoma. A diagnosis of acute myeloid leukaemia was made three months after initial diagnosis by bone marrow examination. Review of the initial biopsy specimen showed strong positivity for myeloperoxidase, revealing that the patient had been initially misdiagnosed as having large B cell lymphoma. Cytogenetic studies revealed a near triploid and near tetraploid karyotype with structural abnormalities in 12 and three metaphases, respectively. Review of the literature showed that a near tetraploid or triploid karyotype is found in most of the reported cases of mediastinal EMMT. Thus, the presence of a near triploid/tetraploid karyotype and mediastinal EMMT may represent a specific subset of EMMT. The biological relevance of this observation is discussed.

Dual mechanism of daunorubicin-induced cell death in both sensitive and MDR-resistant HL-60 cells

Exposure of some acute myeloid leukaemia (AML) cells to daunorubicin leads to rapid cell death, whereas other AML cells show natural drug resistance. This has been attributed to expression of functional P-glycoprotein resulting in reduced drug accumulation. However, it has also been proposed that P-glycoprotein-expressing multidrug-resistant (MDR) cells are inherently defective for apoptosis. To distinguish between these different possibilities, we have compared the cell death process in a human AML cell line (HL-60) with a MDR subline (HL-60/Vinc) at doses that yield either similar intracellular daunorubicin concentrations or comparable cytotoxicity. Adjustment of the dose to obtain the same intracellular drug accumulation in the two cell lines did not result in equal cytotoxicity, suggesting the presence of additional resistance mechanisms in the P-glycoprotein-expressing HL-60/Vinc cells. However, at equitoxic doses, similar cell death pathways were observed. In HL-60 cells, daunorubicin induced rapid apoptosis at 0.5-1 microM and delayed mitotic cell death at 0.1 microM. These concentrations are within the clinical dose range. Similarly, HL-60/Vinc cells underwent apoptosis at 50-100 microM daunorubicin and mitotic cell death at 10 microM. These results show, for the first time, that anthracyclines can induce cell death by a dual mechanism in both sensitive and MDR cells. Our results also show that not only the cytotoxicity, but also the kinetics and mechanism of cell death, are dose dependent. Interestingly, regrowth was observed only in association with delayed cell death and the formation of enlarged, often polyploid, cells with micronucleation, suggesting that morphological criteria may be useful to evaluate treatment efficacy in patients with myeloid leukaemias.