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Summary: Although a growing body of evidence demonstrates that altered mtDNA content (mtDNAc) has clinical implications in several types of solid tumours, its prognostic relevance in acute promyelocytic leukaemia (APL) patients remains largely unknown. Here, we show that patients with higher‐than‐normal mtDNAc had better outcomes regardless of tumour burden. These results were more evident in patients with low‐risk of relapse. The multivariate Cox proportional hazard model demonstrated that high mtDNAc was independently associated with a decreased cumulative incidence of relapse. Altogether, our data highlights the possible role of mitochondrial metabolism in APL patients treated with ATRA. [ABSTRACT FROM AUTHOR]

Outcomes in acute myeloid leukemia (AML) are dependent on patient- and disease-characteristics, treatment, and socioeconomic factors. AML outcomes between resource-constrained and developed countries have not been compared directly. We analyzed two cohorts: from São Paulo state, Brazil (USP, n = 312) and Oxford, United Kingdom (OUH, n = 158). USP cohort had inferior 5-year overall survival compared with OUH (29% vs. 49%, adjusted-p=.027). USP patients have higher early-mortality (23% vs. 6% p<.001) primarily due to multi-resistant Gram-negative bacterial and fungal infections. USP had higher 5-year cumulative incidence of relapse (60% vs. 50%, p=.0022), were less likely to undergo hematopoietic stem cell transplant (HSCT) (28% vs. 75%, p<.001) and waited longer for HSCT (median, 23.8 vs. 7.2 months, p<.001). Three-year survival in relapsed patients was worse in USP than OUH (10% vs. 39%, p<.001). Our study indicates that efforts to improve AML outcomes in Brazil should focus on infection prevention and control, and access to HSCT. [ABSTRACT FROM AUTHOR]

Recurrent vaso-occlusive crises resulting in bone infarction constitute the main cause of osteonecrosis in patients with sickle cell anaemia (SCA) (da Silva Junior I et al., i [10]). Patients with ANXA2*5681 AA genotype (22%, 95% CI: 16-31%) had a significantly higher osteonecrosis development rate compared to patients with non-AA genotype (6%, 95% CI: 4-11%) (P < 0-0001). Genetic assessment of the ANXA2*5681 polymorphism (rs7170178) distribution revealed 44/85 patients (52%) harbouring the ANXA2*5681 non-AA genotype and 41/85 (48%) carrying the ANXA2*5681 AA genotype. To examine the biological impact of I ANXA2 i *5681 polymorphism (rs7170178) at the transcriptional and translational levels, we evaluated 85 new freshly collected samples from patients with SCA who developed (26 patients) or did not develop (59 patients) osteonecrosis. [Extracted from the article]

Simple Summary: In solid tumors, the altered expression of embryonic genes such as the SLIT-ROBO family has been associated with poor prognosis, while little is known about their role in acute myeloid leukemia (AML). Previous studies reported frequent hypermethylation of SLIT2 mediated by the methyltransferase enzyme EZH2 and more recently the PML protein, which are commonly found to be aberrantly expressed in AML. Here, we aim to assess retrospectively the clinical relevance of the SLIT2 gene in acute promyelocytic leukemia, a homogenous subtype of AML. We demonstrated that reduced SLIT2 expression was associated with high leukocyte counts and reduced overall survival in different APL cohorts. STLI2 treatment decreased APL growth, while SLIT2 knockdown accelerated cell cycle progression and proliferation. Finally, reduced expression of SLIT2 in murine APL blasts resulted in fatal leukemia associated with increased leukocyte counts in vivo. These findings demonstrate that SLIT2 can be considered as a prognostic marker in APL, and a potential candidate for clinical studies of a more heterogeneous disease, such as AML. The SLIT-ROBO axis plays an important role in normal stem-cell biology, with possible repercussions on cancer stem cell emergence. Although the Promyelocytic Leukemia (PML) protein can regulate SLIT2 expression in the central nervous system, little is known about SLIT2 in acute promyelocytic leukemia. Hence, we aimed to investigate the levels of SLIT2 in acute promyelocytic leukemia (APL) and assess its biological activity in vitro and in vivo. Our analysis indicated that blasts with SLIT2high transcript levels were associated with cell cycle arrest, while SLIT2low APL blasts displayed a more stem-cell like phenotype. In a retrospective analysis using a cohort of patients treated with all-trans retinoic acid (ATRA) and anthracyclines, high SLIT2 expression was correlated with reduced leukocyte count (p = 0.024), and independently associated with improved overall survival (hazard ratio: 0.94; 95% confidence interval: 0.92–0.97; p < 0.001). Functionally, SLIT2-knockdown in primary APL blasts and cell lines led to increased cell proliferation and resistance to arsenic trioxide induced apoptosis. Finally, in vivo transplant of Slit2-silenced primary APL blasts promoted increased leukocyte count (p = 0.001) and decreased overall survival (p = 0.002) compared with the control. In summary, our data highlight the tumor suppressive function of SLIT2 in APL and its deteriorating effects on disease progression when downregulated. [ABSTRACT FROM AUTHOR]

It is increasingly becoming clear that cancers are a symbiosis of diverse cell types and tumor clones. Combined single-cell RNA sequencing, flow cytometry, and immunohistochemistry studies of the innate immune compartment in the bone marrow of patients with acute myeloid leukemia (AML) reveal a shift toward a tumor-supportive M2-polarized macrophage landscape with an altered transcriptional program, with enhanced fatty acid oxidation and NAD + generation. Functionally, these AML-associated macrophages display decreased phagocytic activity and intra-bone marrow coinjection of M2 macrophages together with leukemic blasts strongly enhances in vivo transformation potential. A 2-day in vitro exposure to M2 macrophages results in the accumulation of CALR low leukemic blast cells, which are now protected against phagocytosis. Moreover, M2-exposed "trained" leukemic blasts display increased mitochondrial metabolism, in part mediated via mitochondrial transfer. Our study provides insight into the mechanisms by which the immune landscape contributes to aggressive leukemia development and provides alternatives for targeting strategies aimed at the tumor microenvironment.

The 2017 European LeukemiaNet 2017 acute myeloid leukemia (AML) risk stratification (ELN2017) is widely used for risk-stratifying patients with AML. However, its applicability in low- and middle-income countries is limited because of a lack of full cytogenetic and molecular information at diagnosis. Here, we propose an alternative for risk stratification (the Adapted Genetic Risk [AGR]), which permits cytogenetic or molecular missing data while retaining prognostic power. We first analyzed 167 intensively treated patients with nonacute promyelocytic leukemia AML enrolled in São Paulo, Brazil (Faculdade de Medicina da Universidade de São Paulo), as our training data set, using ELN2017 as the standard for comparison with our AGR. Next, we combined our AGR with clinical prognostic parameters found in a Cox proportional hazards model to create a novel scoring system (survival AML score, SAMLS) that stratifies patients with newly diagnosed AML. Finally, we have used 2 independent test cohorts, Faculdade de Medicina de Ribeirão Preto (FMRP; Brazil, n = 145) and Oxford University Hospitals (OUH; United Kingdom, n = 157) for validating our findings. AGR was statistically significant for overall survival (OS) in both test cohorts (FMRP, P = .037; OUH, P = .012) and disease-free survival in FMRP (P = .04). The clinical prognostic features in SAMLS were age (>45 years), white blood cell count (<1.5 or >30.0 × 103/μL), and low albumin levels (<3.8 g/dL), which were associated with worse OS in all 3 cohorts. SAMLS showed a significant difference in OS in the training cohort (P < .001) and test cohorts (FMRP, P = .0018; OUH, P < .001). Therefore, SAMLS, which incorporates the novel AGR evaluation with clinical parameters, is an accurate tool for AML risk assessment., (© 2020 by The American Society of Hematology.)