Clinical Characteristics and Outcomes of a Cohort of Pediatric Oncohematologic Patients With COVID-19 Infection in the City of Bogotá, Colombia.

BACKGROUND: In children, the complications of severe acute respiratory syndrome coronavirus 2 infection occur less frequently than in adults but the characteristics of this disease in oncology patients are not well characterized. METHODS: This was a retrospective study in patients younger than 18 years of age with coronavirus disease 2019 (COVID-19) and cancer diagnoses between April and September 2020. Demographic variables, laboratory, and radiologic findings and complications of each case were identified. A descriptive analysis was performed. RESULTS: A total of 33 patients were identified; the median age was 10 years. Fifteen patients (42%) were in chemotherapy at the time of the infection diagnosis, in two patients the chemotherapy protocol was permanently suspended. The most common symptom was fever in 20 patients (60%). Seven patients (21.2%) showed mild pneumonia, four patients (12.1%) severe pneumonia, and three cases (9.0%) were classified as critical. In the evaluated cohort, five patients (15.1%) died, and in two of those, death was caused by COVID-19 infection. CONCLUSIONS: Children with an oncologic disease, the search for COVID cases should be oriented to patients with fever, including febrile neutropenia, the presence of respiratory symptoms, and the search for epidemiologic contact. A higher frequency of complications and mortality attributed to COVID-19, two in pediatric oncohematologic patients was found. Institutional strategies to detect the infection early and lower institutional infection are indicated.

Diversity, localization, and (patho)physiology of mature lymphocyte populations in the bone marrow.

The bone marrow (BM) is responsible for generating and maintaining lifelong output of blood and immune cells. In addition to its key hematopoietic function, the BM acts as an important lymphoid organ, hosting a large variety of mature lymphocyte populations, including B cells, T cells, natural killer T cells, and innate lymphoid cells. Many of these cell types are thought to visit the BM only transiently, but for others, like plasma cells and memory T cells, the BM provides supportive niches that promote their long-term survival. Interestingly, accumulating evidence points toward an important role for mature lymphocytes in the regulation of hematopoietic stem cells (HSCs) and hematopoiesis in health and disease. In this review, we describe the diversity, migration, localization, and function of mature lymphocyte populations in murine and human BM, focusing on their role in immunity and hematopoiesis. We also address how various BM lymphocyte subsets contribute to the development of aplastic anemia and immune thrombocytopenia, illustrating the complexity of these BM disorders and the underlying similarities and differences in their disease pathophysiology. Finally, we summarize the interactions between mature lymphocytes and BM resident cells in HSC transplantation and graft-versus-host disease. A better understanding of the mechanisms by which mature lymphocyte populations regulate BM function will likely improve future therapies for patients with benign and malignant hematologic disorders.

COVID-19 in patients with cancer: Risks and precautions.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a member of the coronavirus family, which causes coronavirus disease 2019 (COVID-19). The phenotype of the disease varies from asymptomatic, to a mild phenotype, through to the severe form of acute respiratory distress syndrome (ARDS), which often leads to death, especially in those with underlying diseases. It has been reported that those who suffer from cancer (especially lung cancer and hematological malignancies) are at higher risk of serious complications and death from COVID-19. Some cancer treatments such as CAR T cell therapy can produce a cytokine storm, which is also a hallmark of severe COVID-19. Therefore, patients receiving CAR T cells are at higher risk if they become infected with COVID-19, and could be treated with anti-cytokine approaches.

Multidirectional Walking in Hematopoietic Stem Cell Transplant Patients.

BACKGROUND: The effect of a peritransplant multidirectional walking intervention to target losses in physical function and quality of life (QOL) has not been investigated. PURPOSE: This study examined the effects of a novel multidirectional walking program on physical function and QOL in adults receiving a hematopoietic stem cell transplant (HSCT). METHODS: Thirty-five adults receiving an autologous or allogeneic HSCT were randomized to a multidirectional walking (WALK) or usual care (CONT) group. The WALK group received supervised training during hospitalization; the CONT group received usual care. Patients were assessed at admission (t0), 3 to 5 d post-HSCT (t1), and 30 d post-HSCT (t2). Physical function measures included the 6-min walk test (6MWT), the Physical Performance Test, and the Timed Up and Go test. Health-related QOL was collected using the Functional Assessment of Cancer Therapy-Bone Marrow Transplant (FACT-BMT) questionnaire. RESULTS: There were no significant between-group changes for physical function or QOL. However, after the intervention (t1 to t2), the WALK group showed significant improvement in aerobic capacity (6MWT, P = 0.01), physical (P < 0.01) and functional well-being (P = 0.04), and overall QOL scores (P < 0.01). The CONT group saw no significant changes in physical function or QOL. Effect sizes showed the WALK group had a larger positive effect on physical function and QOL. Minimal clinically important differences in the 6MWT and FACT-BMT were exceeded in the WALK group. CONCLUSION: A multidirectional walking program during the transplant period may be effective at increasing aerobic capacity and QOL for patients receiving HSCT compared with no structured exercise.

Gait speed, survival, and recommended treatment intensity in older adults with blood cancer requiring treatment.

BACKGROUND: Brief measures of physical function such as gait speed may be useful to optimize treatment intensity for older adults who have blood cancer; however, little is known about whether such assessments are already captured within oncologists' "gestalt" assessments. METHODS: Gait speed was assessed in 782 patients ≥75 years of age who had blood cancer, with results reported to providers after treatment decisions were made; 408 patients required treatment when different intensities were available per National Comprehensive Cancer Network (NCCN) guidelines. We performed structured abstractions of treatment intensity recommendations into standard intensity, reduced intensity, or supportive care, based on NCCN guidelines. We modeled gait speed and survival using Cox regression and performed ordinal logistic regression to assess predictors of NCCN-based categorizations of oncologists' treatment intensity recommendations, including gait speed. RESULTS: The median survival by gait speed category was 10.8 months (<0.4 m/s), 18.6 months (0.4-0.6 m/s), 34.0 months (0.6-0.8 m/s), and unreached (>0.8 m/s). Univariable hazard ratios (HRs) for death increased for each lower category compared with ≥0.8 m/s (0.6-0.8 m/s: HR, 1.76; 0.4-0.6 m/s: HR, 2.30; <0.4 m/s: HR, 3.31). Gait speed predicted survival in multivariable Cox regression (all P < .05). In multivariable models including age, sex, and Eastern Cooperative Oncology Group performance status, gait speed did not predict oncologists' recommended treatment intensity (all P > .05) and did not add to a base model predicting recommended treatment intensity. CONCLUSION: In older adults with blood cancer who presented for treatment, gait speed predicted survival but not treatment intensity recommendation. Incorporating gait speed into decision making may improve optimal treatment selection.

Targeting DNA Repair Pathways in Hematological Malignancies.

DNA repair plays an essential role in protecting cells that are repeatedly exposed to endogenous or exogenous insults that can induce varying degrees of DNA damage. Any defect in DNA repair mechanisms results in multiple genomic changes that ultimately may result in mutation, tumor growth, and/or cell apoptosis. Furthermore, impaired repair mechanisms can also lead to genomic instability, which can initiate tumorigenesis and development of hematological malignancy. This review discusses recent findings and highlights the importance of DNA repair components and the impact of their aberrations on hematological malignancies.

Zebrafish blood disease models and applications.

Hematopoiesis is a complex, orderly and conserved developmental process, coordinated by multiple factors including transcription factors and signaling pathways. Dysregulation of any of these factors may cause developmental or functional defects in the blood system, leading to the pathogenesis of blood diseases. Zebrafish hematopoiesis and the underlying molecular mechanisms are highly conserved with those in mammals. The use of zebrafish to recapitulate abnormal changes in pathogenic factors can build models of related blood diseases, thus providing powerful tools for exploring the molecular mechanisms of pathogenesis and progression, visualization of tumorigenesis and high-throughput chemical screening. In this review, we summarize the zebrafish models of blood diseases and their applications. These disease models not only help to improve our understanding of the pathophysiology of the blood system and the molecular mechanisms on pathogeneses of blood diseases, but also provide new ideas for the treatment of clinically relevant hematological malignancies.

A WEE1 family business: regulation of mitosis, cancer progression, and therapeutic target.

The inhibition of the DNA damage response (DDR) pathway in the treatment of cancer has recently gained interest, and different DDR inhibitors have been developed. Among them, the most promising ones target the WEE1 kinase family, which has a crucial role in cell cycle regulation and DNA damage identification and repair in both nonmalignant and cancer cells. This review recapitulates and discusses the most recent findings on the biological function of WEE1/PKMYT1 during the cell cycle and in the DNA damage repair, with a focus on their dual role as tumor suppressors in nonmalignant cells and pseudo-oncogenes in cancer cells. We here report the available data on the molecular and functional alterations of WEE1/PKMYT1 kinases in both hematological and solid tumors. Moreover, we summarize the preclinical information on 36 chemo/radiotherapy agents, and in particular their effect on cell cycle checkpoints and on the cellular WEE1/PKMYT1-dependent response. Finally, this review outlines the most important pre-clinical and clinical data available on the efficacy of WEE1/PKMYT1 inhibitors in monotherapy and in combination with chemo/radiotherapy agents or with other selective inhibitors currently used or under evaluation for the treatment of cancer patients.

Precision-based exercise as a new therapeutic option for children and adolescents with haematological malignancies.

Children and adolescents with haematological malignancies (PedHM) are characterized by a severe loss of exercise ability during cancer treatment, lasting throughout their lives once healed and impacting their social inclusion prospects. The investigation of the effect of a precision-based exercise program on the connections between systems of the body in PedHM patients is the new frontier in clinical exercise physiology. This study is aimed at evaluating the effects of 11 weeks (3 times weekly) of combined training (cardiorespiratory, resistance, balance and flexibility) on the exercise intolerance in PedHM patients. Two-hundred twenty-six PedHM patients were recruited (47% F). High or medium frequency participation (HAd and MAd) was considered when a participant joined; > 65% or between 30% and < 64% of training sessions, respectively. The "up and down stairs'' test (TUDS), "6 min walking" test (6MWT), the "5 Repetition Maximum strength" leg extension and arm lateral raise test (5RM-LE and 5RM-ALR), flexibility (stand and reach), and balance (stabilometry), were performed and evaluated before and after training. The TUDS, the 5RM-LE and 5RM-ALR, and the flexibility exercises showed an increase in HAd and MAd groups (P < 0.05), while the 6MWT and balance tests showed improvement only in HAd group (P < 0.0001). These results support the ever-growing theory that, in the case of the treatment of PedHM, 'exercise is medicine' and it has the potential to increase the patient's chances of social inclusion.

The role of circular RNAs in hematological malignancies.

Circular RNAs (circRNAs) are a class of noncoding RNAs (ncRNAs) that lack a 5' end cap or a 3' end poly-(A) tail and form a circular structure through covalent bonds. Compared to linear RNAs, circRNAs are more conservative and stable, and their distribution is spatiotemporally regulated. circRNAs, as a new type of competitive endogenous RNA (ceRNA), are involved in many disease processes and are also related to the occurrence and development of tumors. Over the past three years, the role of circRNAs in hematological malignancies has received increasing attention. Related research has shown that circRNAs may regulate the occurrence and development of hematological malignancies and contribute to drug resistance through a variety of molecular mechanisms. Therefore, to lay the foundation and point out directions for further research on circRNAs, this article systematically reviews the research progress on circRNAs in leukemia, lymphoma, and myeloma.

Role of CD47 in Hematological Malignancies.

CD47, or integrin-associated protein, is a cell surface ligand expressed in low levels by nearly all cells of the body. It plays an integral role in various immune responses as well as autoimmunity, by sending a potent "don't eat me" signal to prevent phagocytosis. A growing body of evidence demonstrates that CD47 is overexpressed in various hematological malignancies and its interaction with SIRPα on the phagocytic cells prevents phagocytosis of cancer cells. Additionally, it is expressed by different cell types in the tumor microenvironment and is required for establishing tumor metastasis. Overexpression of CD47 is thus often associated with poor clinical outcomes. CD47 has emerged as a potential therapeutic target and is being investigated in various preclinical studies as well as clinical trials to prove its safety and efficacy in treating hematological neoplasms. This review focuses on different therapeutic mechanisms to target CD47, either alone or in combination with other cell surface markers, and its pivotal role in impairing tumor growth and metastatic spread of various types of hematological malignancies.

Tattoos and Hematologic Malignancies in British Columbia, Canada.

BACKGROUND: Tattoos may cause a variety of adverse reactions in the body, including immune reactions and infections. However, it is unknown whether tattoos may increase the risk of lymphatic cancers such as non-Hodgkin lymphoma (NHL) and multiple myeloma. METHODS: Participants from two population-based case-control studies were included in logistic regression models to examine the association between tattoos and risk of NHL and multiple myeloma. RESULTS: A total of 1,518 participants from the NHL study (737 cases) and 742 participants from the multiple myeloma study (373 cases) were included in the analyses. No statistically significant associations were found between tattoos and risk of NHL or multiple myeloma after adjusting for age, sex, ethnicity, education, body mass index, and family history. CONCLUSIONS: We did not identify any significant associations between tattoos and risk of multiple myeloma, NHL, or NHL subtypes in these studies. IMPACT: Though biologically plausible, tattoos were not associated with increased risk of NHL or multiple myeloma in this study. Future studies with greater detail regarding tattoo exposure may provide further insights.

Effects of Hormone Replacement Therapy on Bone Mass After Allogeneic Hematopoietic Stem Cell Transplantation.

CONTEXT AND OBJECTIVES: This study aimed to assess the effects of hormone replacement therapy (HRT) on bone mineral density (BMD) in young women who underwent allogeneic hematopoietic stem cell transplantation (HSCT). PARTICIPANTS AND METHODS: This retrospective cohort included 234 female patients with premature ovarian insufficiency (POI) who underwent allogeneic HSCT between April 2009 and April 2016 at Seoul St. Mary's Hospital in Seoul, Korea. Inclusion criteria included adult patients who were age 40 years or younger at the time of transplantation and were followed for at least 3 years after HSCT. RESULTS: At the first and second years after HRT, there was a significant increase in the BMD of the lumbar spine of the HRT group (n = 170) compared to that of the non-HRT group (n = 64) (P = .033 and P = .047, respectively). The BMD of the lumbar spine significantly increased from baseline by 4.16 ±â€…4.39% and 5.42 ±â€…5.86% after 1 and 2 years of HRT, respectively (P = .037 and P = .021). The BMD of the femoral neck and total hip also showed a significant percentage increase from baseline after 2 years of HRT. These changes were significant even in the presence of graft-versus-host disease or steroid exposure. For HRT that was initiated within 12 months after HSCT, the increase in BMD in the lumbar spine was greatest after 2 years of HRT. CONCLUSIONS: These results support that early and active hormonal therapy might be beneficial for BMD in female HSCT recipients with POI.

Global dynamics of healthy and cancer cells competing in the hematopoietic system.

Stem cells in the bone marrow differentiate to ultimately become mature, functioning blood cells through a tightly regulated process (hematopoiesis) including a stem cell niche interaction and feedback through the immune system. Mutations in a hematopoietic stem cell can create a cancer stem cell leading to a less controlled production of malfunctioning cells in the hematopoietic system. This was mathematically modelled by Andersen et al. (2017) including the dynamic variables: healthy and cancer stem cells and mature cells, dead cells and an immune system response. Here, we apply a quasi steady state approximation to this model to construct a two dimensional model with four algebraic equations denoted the simple cancitis model. The two dynamic variables are the clinically available quantities JAK2V617F allele burden and the number of white blood cells. The simple cancitis model represents the original model very well. Complete phase space analysis of the simple cancitis model is performed, including proving the existence and location of globally attracting steady states. Hence, parameter values from compartments of stem cells, mature cells and immune cells are directly linked to disease and treatment prognosis, showing the crucial importance of early intervention. The simple cancitis model allows for a complete analysis of the long term evolution of trajectories. In particular, the value of the self renewal of the hematopoietic stem cells divided by the self renewal of the cancer stem cells is found to be an important diagnostic marker and perturbing this parameter value at intervention allows the model to reproduce clinical data. Treatment at low cancer cell numbers allows returning to healthy blood production while the same intervention at a later disease stage can lead to eradication of healthy blood producing cells. Assuming the total number of white blood cells is constant in the early cancer phase while the allele burden increases, a one dimensional model is suggested and explicitly solved, including parameters from all original compartments. The solution explicitly shows that exogenous inflammation promotes blood cancer when cancer stem cells reproduce more efficiently than hematopoietic stem cells.

How I treat pain in hematologic malignancies safely with opioid therapy.

The field of malignant hematology has experienced extraordinary advancements with survival rates doubling for many disorders. As a result, many life-threatening conditions have since evolved into chronic medical ailments. Paralleling these advancements have been increasing rates of complex hematologic pain syndromes, present in up to 60% of patients with malignancy who are receiving active treatment and up to 33% of patients during survivorship. Opioids remain the practice cornerstone to managing malignancy-associated pain. Prevention and management of opioid-related complications have received significant national attention over the past decade, and emerging data suggest that patients with cancer are at equal if not higher risk of opioid-related complications when compared with patients without malignancy. Numerous tools and procedural practice guides are available to help facilitate safe prescribing. The recent development of cancer-specific resources directing algorithmic use of validated pain screening tools, prescription drug monitoring programs, urine drug screens, opioid use disorder risk screening instruments, and controlled substance agreements have further strengthened the framework for safe prescribing. This article, which integrates federal and organizational guidelines with known risk factors for cancer patients, offers a case-based discussion for reviewing safe opioid prescribing practices in the hematology setting.

Bone marrow niches in haematological malignancies.

Haematological malignancies were previously thought to be driven solely by genetic or epigenetic lesions within haematopoietic cells. However, the niches that maintain and regulate daily production of blood and immune cells are now increasingly being recognized as having an important role in the pathogenesis and chemoresistance of haematological malignancies. Within haematopoietic cells, the accumulation of a small number of recurrent mutations initiates malignancy. Concomitantly, specific alterations of the niches, which support haematopoietic stem cells and their progeny, can act as predisposition events, facilitating mutant haematopoietic cell survival and expansion as well as contributing to malignancy progression and providing protection of malignant cells from chemotherapy, ultimately leading to relapse. In this Perspective, we summarize our current understanding of the composition and function of the specialized haematopoietic niches of the bone marrow during health and disease. We discuss disease mechanisms (rather than malignancy subtypes) to provide a comprehensive description of key niche-associated pathways that are shared across multiple haematological malignancies. These mechanisms include primary driver mutations in bone marrow niche cells, changes associated with increased hypoxia, angiogenesis and inflammation as well as metabolic reprogramming by stromal niche cells. Consequently, remodelling of bone marrow niches can facilitate immune evasion and activation of survival pathways favouring malignant haematopoietic cell maintenance, defence against excessive reactive oxygen species and protection from chemotherapy. Lastly, we suggest guidelines for the handling and biobanking of patient samples and analysis of the niche to ensure that basic research identifying therapeutic targets can be more efficiently translated to the clinic. The hope is that integrating knowledge of how bone marrow niches contribute to haematological disease predisposition, initiation, progression and response to therapy into future clinical practice will likely improve the treatment of these disorders.