Clinical Implications of Clonal Hematopoiesis

Clonal Hematopoiesis of Indeterminate Potential and Cardiovascular Health

Clonal hematopoiesis of indeterminate potential (CHIP) is an age-related phenomenon in which somatic mutations lead to clonal expansion of hematopoietic stem cells without the development of hematologic abnormalities. A growing body of literature demonstrates an association between CHIP and cardiovascular disease. This pathophysiology demonstrates a novel connection between global inflammation and cardiovascular morbidity. While there is limited consensus addressing the cardiovascular care of these patients, risk factor optimization and disease surveillance are advisable. Investigation into possible therapies is ongoing and provides promise for the treatment of inflammation contributing to cardiovascular disease in patients with and without CHIP.

Red cell distribution width: a potential marker of reduced femoral neck bone mineral density in men and postmenopausal women

PURPOSE

Osteoporosis imposes significant burdens. Early detection of high-risk individuals through simple indicators can greatly improve prognosis. Red cell distribution width (RDW), a standard component of a complete blood count, shows promise, yet remains underexplored. This cross-sectional study aimed to investigate the association between RDW and femoral neck and spinal bone mineral density (BMD).

METHODS

Participants aged 20-79 years from the 2005-2010, 2013-2014, and 2017-2020 cycles of the National Health and Nutrition Examination Survey (NHANES) were included. BMD was measured using dual-energy X-ray absorptiometry (DXA).

RESULTS

A total of 13,029 participants were included, comprising 6684 men, 3238 postmenopausal women, and 3107 premenopausal women, with the sample weighted to represent 98,712,128 people. After adjusting for covariates, RDW exhibited a negative association with femoral neck BMD in both men (β = -0.006; 95% CI: -0.010 to -0.002; p = 0.0053) and postmenopausal women (β = -0.005; 95% CI: -0.010 to -0.000; p = 0.0413). Subgroup and sensitivity analyses supported the robustness of these findings. A negative association between RDW and spinal BMD in men approached significance (β = -0.004; 95% CI: -0.008 to 0.000; p = 0.0557). Persistent trends were observed for RDW with spinal BMD in postmenopausal women and with both femoral neck and spinal BMD in premenopausal women.

CONCLUSIONS

Our study suggests a negative association between RDW and femoral neck BMD in both men and postmenopausal women. These findings highlight the potential of RDW as a marker for identifying individuals at higher risk of osteoporosis.

Clonal Hematopoiesis and Clinical Outcomes in Metastatic Castration-Resistant Prostate Cancer Patients Given Androgen Receptor Pathway Inhibitors (Alliance A031201)

PURPOSE

Mutations in hematopoietic progenitor cells accumulate with age leading to clonal expansion, termed clonal hematopoiesis (CH). CH in the general population is associated with hematopoietic neoplasms and reduced overall survival (OS), predominantly through cardiovascular adverse events (CVAE). Because androgen receptor pathway inhibitors (ARPI) used in metastatic castration-resistant prostate cancer (mCRPC) are also associated with CVAEs and because CH negatively impacted survival in an advanced solid tumor cohort, we hypothesized that CH in mCRPC may be associated with increased CVAEs and inferior survival.

EXPERIMENTAL DESIGN

A targeted DNA sequencing panel captured common CH mutations in pretreatment blood samples from 957 patients enrolled in Alliance A031201: a randomized trial of enzalutamide ± abiraterone/prednisone in the first-line mCRPC setting. The primary outcome was the impact of CH on OS; the secondary outcomes were progression-free survival (PFS) and CVAEs.

RESULTS

Baseline comorbidities were similar by CH status. No differences in OS/progression-free survival were detected regardless of treatment arm or the variant allele frequency threshold used to define CH [primary: 2% (normal-CH, N-CH); exploratory: 0.5% (low-CH) and 10% (high-CH, H-CH)]. Patients with H-CH (7.2%) and TET2-mutated N-CH (6.0%) had greater odds of any CVAE (14.5% vs. 4.0%; P = 0.0004 and 12.3% vs. 4.2%; P = 0.010, respectively). More major CVAEs were observed in patients with H-CH (5.8% vs. 1.9%; P = 0.042) and N-CH (3.4% vs. 1.8%; P = 0.147).

CONCLUSIONS

CH did not affect survival in patients with mCRPC treated with ARPIs in A031201. H-CH and TET2-mutated CH were associated with more CVAEs. These findings inform the risk/benefit discussion about ARPIs in mCRPC.

Red cell size factor is a sensitive index in the early diagnosis of nondigestive tract cancer-related anemia: An observational study

Cancer-related anemia (CRA) is a common comorbidity in cancer patients, and it can lead to a worse prognosis. The aim of this cross-sectional study is to investigate the clinical value of the red cell size factor (Rsf) in the early diagnosis of nondigestive tract CRA. A total of 231 patients with nondigestive tract solid cancer were included, and they were divided into anemic and nonanemic subjects according to the hemoglobin (Hb) levels. A BC-7500 blood analyzer was used to detect the indices of red blood cell and reticulocyte, and the mean corpuscular volume (MCV), mean reticulocyte volume (MRV), reticulocyte hemoglobin (RHE) content, and reticulocyte production index were observed. Subsequently, the Rsf was calculated. Receiver operating characteristic curve analysis was used to evaluate the identifying power of Rsf for anemia diagnosed by the combination of RHE and reticulocyte production index. The adjusted-multivariate analysis and quartiles were used to assess the relation of reduced Rsf level with the risk and incidence of anemia diagnosed by combining the MCV, MCH, and mean corpuscular hemoglobin concentration (MCHC), respectively. Rsf levels showed no statistical differences between anemia and nonanemia subjects grouped by Hb (P > .05). Rsf has a high correlation with the RHE level (R > 0.900, P < .001), or MCV, mean corpuscular hemoglobin (MCH), and MCHC in anemia patients (r: 0.435-0.802, P < .001). Receiver operating characteristic curves showed that Rsf had the highest overall area under curve of 0.886 (95% confidence interval: 0.845-0.927) in identifying anemia of cancer patients (P < .001). When the optimal cutoff values of Rsf were set at 97.05 fl in males and 94.95 fl in females, the sensitivity and specificity were 0.94 and 0.76, and 0.98 and 0.75, respectively. Being treated as a categorical variable, Rsf had a highest odds ratio value of 30.626 (12.552-74.726; P < .001) for the risk of anemia. The increment of Rsf quartiles was highly associated with the decreased incidence of overall anemia (P trend < 0.001). The study suggests that decreased Rsf level is a potentially powerful predictor of overt anemia in nondigestive tract cancer, and it can be used as a convenient, practical, cost-free, and sensitive index in early diagnosis of nondigestive tract CRA.

An approach for developing a blood-based screening panel for lung cancer based on clonal hematopoietic mutations

Early detection can significantly reduce mortality due to lung cancer. Presented here is an approach for developing a blood-based screening panel based on clonal hematopoietic mutations. Animal model studies suggest that clonal hematopoietic mutations in tumor infiltrating immune cells can modulate cancer progression, representing potential predictive biomarkers. The goal of this study was to determine if the clonal expansion of these mutations in blood samples could predict the occurrence of lung cancer. A set of 98 potentially pathogenic clonal hematopoietic mutations in tumor infiltrating immune cells were identified using sequencing data from lung cancer samples. These mutations were used as predictors to develop a logistic regression machine learning model. The model was tested on sequencing data from a separate set of 578 lung cancer and 545 non-cancer samples from 18 different cohorts. The logistic regression model correctly classified lung cancer and non-cancer blood samples with 94.12% sensitivity (95% Confidence Interval: 92.20-96.04%) and 85.96% specificity (95% Confidence Interval: 82.98-88.95%). Our results suggest that it may be possible to develop an accurate blood-based lung cancer screening panel using this approach. Unlike most other "liquid biopsies" currently under development, the approach presented here is based on standard sequencing protocols and uses a relatively small number of rationally selected mutations as predictors.

Clonal hematopoiesis driven by mutated DNMT3A promotes inflammatory bone loss

Clonal hematopoiesis of indeterminate potential (CHIP) arises from aging-associated acquired mutations in hematopoietic progenitors, which display clonal expansion and produce phenotypically altered leukocytes. We associated CHIP-DNMT3A mutations with a higher prevalence of periodontitis and gingival inflammation among 4,946 community-dwelling adults. To model DNMT3A-driven CHIP, we used mice with the heterozygous loss-of-function mutation R878H, equivalent to the human hotspot mutation R882H. Partial transplantation with Dnmt3aR878H/+ bone marrow (BM) cells resulted in clonal expansion of mutant cells into both myeloid and lymphoid lineages and an elevated abundance of osteoclast precursors in the BM and osteoclastogenic macrophages in the periphery. DNMT3A-driven clonal hematopoiesis in recipient mice promoted naturally occurring periodontitis and aggravated experimentally induced periodontitis and arthritis, associated with enhanced osteoclastogenesis, IL-17-dependent inflammation and neutrophil responses, and impaired regulatory T cell immunosuppressive activity. DNMT3A-driven clonal hematopoiesis and, subsequently, periodontitis were suppressed by rapamycin treatment. DNMT3A-driven CHIP represents a treatable state of maladaptive hematopoiesis promoting inflammatory bone loss.

Aging and Age-Related Epigenetic Drift in the Pathogenesis of Leukemia and Lymphomas: New Therapeutic Targets

One of the traits of cancer cells is abnormal DNA methylation patterns. The idea that age-related epigenetic changes may partially explain the increased risk of cancer in the elderly is based on the observation that aging is also accompanied by comparable changes in epigenetic patterns. Lineage bias and decreased stem cell function are signs of hematopoietic stem cell compartment aging. Additionally, aging in the hematopoietic system and the stem cell niche have a role in hematopoietic stem cell phenotypes linked with age, such as leukemia and lymphoma. Understanding these changes will open up promising pathways for therapies against age-related disorders because epigenetic mechanisms are reversible. Additionally, the development of high-throughput epigenome mapping technologies will make it possible to identify the "epigenomic identity card" of every hematological disease as well as every patient, opening up the possibility of finding novel molecular biomarkers that can be used for diagnosis, prediction, and prognosis.

Pure red cell aplasia: The second hundred years

Pure red cell aplasia (PRCA) is a rare hematologic syndrome, characterized by an isolated normocytic anemia with severe reticulocytopenia, and defined by absence or near absence of erythroid precursors in the bone marrow. First described in 1922, PRCA may be a primary autoimmune or clonal myeloid or lymphoid disorder, but may also be secondary to other disorders of immune dysregulation/autoimmunity, to infections, to neoplasms, or to drugs. Insights from the study of PRCA have helped illuminate the understanding of the regulation of erythropoiesis. This review summarizes the classification, diagnostic, and therapeutic approach to PRCA as it begins its second century, with a particular focus on opportunities and challenges provided by new developments in the role of T-cells and T-cell regulatory mutations; the role of clonal hematopoiesis; and new developments in therapy for refractory PRCA and PRCA associated with ABO incompatible stem cell transplantation.

Potential immunosuppressive clonal hematopoietic mutations in tumor infiltrating immune cells in breast invasive carcinoma

A hallmark of cancer is a tumor cell's ability to evade immune destruction. Somatic mutations in tumor cells that prevent immune destruction have been extensively studied. However, somatic mutations in tumor infiltrating immune (TII) cells, to our knowledge, have not been previously studied. Understandably so since normal hematopoiesis prevents the accumulation of somatic mutations in immune cells. However, clonal hematopoiesis does result in the accumulation of somatic mutations in immune cells. These mutations cannot "drive" tumor growth, however, they may "facilitate" it by inhibiting an effective anti-tumor immune response. To identify potential immunosuppressive clonal hematopoietic (CH) mutations in TII cells, we analyzed exome and RNA sequencing data from matched tumor and normal blood samples, and single-cell RNA sequencing data, from breast cancer patients. We selected mutations that were somatic, present in TII cells, clonally expanded, potentially pathogenic, expressed in TII cells, unlikely to be a passenger mutation, and in immune response associated genes. We identified eight potential immunosuppressive CH mutations in TII cells. This work is a first step towards determining if immunosuppressive CH mutations in TII cells can affect the progression of solid tumors. Subsequent experimental confirmation could represent a new paradigm in the etiology of cancer.

Acute Oncologic Complications: Clinical-Therapeutic Management in Critical Care and Emergency Departments

Introduction. It is now known that cancer is a major public health problem; on the other hand, it is less known, or rather, often underestimated, that a significant percentage of cancer patients will experience a cancer-related emergency. These conditions, depending on the severity, may require treatment in intensive care or in the emergency departments. In addition, it is not uncommon for a tumor pathology to manifest itself directly, in the first instance, with a related emergency. The emergency unit proves to be a fundamental and central unit in the management of cancer patients. Many cancer cases are diagnosed in the first instance as a result of symptoms that lead the patient's admittance into the emergency room. Materials and Methods. This narrative review aims to analyze the impact of acute oncological cases in the emergency setting and the role of the emergency physician in their management. A search was conducted over the period January 1981-April 2023 using the main scientific platforms, including PubMed, Scopus, Medline, Embase and Google scholar, and 156 papers were analyzed. Results. To probe into the main oncological emergencies and their management in increasingly overcrowded emergency departments, we analyzed the following acute pathologies: neurological emergencies, metabolic and endocrinological emergencies, vascular emergencies, malignant effusions, neutropenic fever and anemia. Discussion/Conclusions. Our analysis found that a redefinition of the emergency department connected with the treatment of oncology patients is necessary, considering not only the treatment of the oncological disease in the strict sense, but also the comorbidities, the oncological emergencies and the palliative care setting. The need to redesign an emergency department that is able to manage acute oncological cases and end of life appears clear, especially when this turns out to be related to severe effects that cannot be managed at home with integrated home care. In conclusion, a redefinition of the paradigm appears mandatory, such as the integration between the various specialists belonging to oncological medicine and the emergency department. Therefore, our work aims to provide what can be a handbook to detect, diagnose and treat oncological emergencies, hoping for patient management in a multidisciplinary perspective, which could also lead to the regular presence of an oncologist in the emergency room.

Clinical utility of liquid biopsy and integrative genomic profiling in early-stage and oligometastatic cancer patients treated with radiotherapy

BACKGROUND

Liquid biopsy and Integrative Genomic Profiling (IGP) are yet to be implemented into routine Radiation Oncology. Here we assess the utility of germline, tumour and circulating cell-free DNA-based genomic analyses for the clinical management of early-stage and oligometastatic cancer patients treated by precision radiotherapy.

METHODS

We performed germline, tissue- and liquid biopsy NGS panels on 50 early-stage/oligometastatic cancer patients undergoing radiotherapy. We also monitored ctDNA variants in serial liquid biopsies collected during radiotherapy and follow-up and evaluated the clinical utility of such comprehensive approach.

RESULTS

The integration of different genomic studies revealed that only 1/3 of the liquid biopsy variants are of tumour origin. Altogether, 55 tumour variants (affecting 3/4 of the patients) were considered potentially actionable (for treatment and prognosis), whereas potential follow-up biomarkers were identified in all cases. Germline cancer-predisposing variants were present in three patients, which would have not been eligible for hereditary cancer testing according to clinical guidelines. The presence of detectable ctDNA variants before radiotherapy was associated with progression-free survival both in oligometastatic patients and in those with early-stage.

CONCLUSIONS

IGP provides both valuable and actionable information for personalised decision-making in Radiation Oncology.

Circulating tumor DNA in early-stage colon cancer: ready for prime time or needing refinement?

Liquid biopsies are the detection of molecular information in fluids from patients with cancer. In colorectal cancer (CRC), the most promising liquid biopsy strategy is the use of circulating tumor DNA (ctDNA) from plasma. In early-stage CRC, the potential for ctDNA to impact care stems from the detection of minimal residual disease (MRD) to guide adjuvant therapy after curative intent treatment and in identifying recurrences during surveillance. As for any new diagnostic test, ctDNA assays must overcome pre-analytical and analytical challenges before clinical implementation. We will discuss important logistical and assay considerations that clinicians and patients should understand when assessing ctDNA assays. We will also delve into important concepts to aid in interpreting ctDNA results and potential incidental findings that may arise. Sequencing errors, germline variants, and clonal hematopoiesis of indeterminate potential (CHIP) must be addressed to properly interpret results. CHIP is also an important consideration that impacts patient prognosis through association with cardiovascular and hematologic diseases. With this background in place, we next review the best available evidence for the use of ctDNA in early-stage colon cancer. Observational cohorts have established MRD after surgery as a significant prognostic factor for recurrence in stage II and III colon cancer. It also has the ability to anticipate clinical recurrence before standard investigations when used in surveillance. The first and only interventional randomized trial to date evaluating ctDNA is DYNAMIC. The study demonstrated the noninferiority of a MRD detection-guided approach in selecting patients with stage II colon cancer for adjuvant treatment. Notwithstanding the important results, there are still important questions to be answered before ctDNA enters prime time in the clinic. However, future appears bright and ongoing trials will help clarify how to best use this technology in early-stage colon cancer.

Retrospective analysis of somatic mutations and clonal hematopoiesis in astronauts

With planned deep space and commercial spaceflights, gaps remain to address health risks in astronauts. Multiple studies have shown associations between clonal expansion of hematopoietic cells with hematopoietic malignancies and cardiometabolic disease. This expansion of clones in the absence of overt hematopoietic disorders is termed clonal hematopoiesis (CH) of indeterminate potential (CHIP). Using deep, error-corrected, targeted DNA sequencing we assayed for somatic mutations in CH-driver genes in peripheral blood mononuclear cells isolated from de-identified blood samples collected from 14 astronauts who flew Shuttle missions between 1998-2001. We identified 34 nonsynonymous mutations of relatively low variant allele fraction in 17 CH-driver genes, with the most prevalent mutations in TP53 and DNMT3A. The presence of these small clones in the blood of relatively young astronaut cohort warrants further retrospective and prospective investigation of their clinical relevance and potential application in monitoring astronaut's health.

Human Variation in DNA Repair, Immune Function, and Cancer Risk

DNA damage constantly threatens genome integrity, and DNA repair deficiency is associated with increased cancer risk. An intuitive and widely accepted explanation for this relationship is that unrepaired DNA damage leads to carcinogenesis due to the accumulation of mutations in somatic cells. But DNA repair also plays key roles in the function of immune cells, and immunodeficiency is an important risk factor for many cancers. Thus, it is possible that emerging links between inter-individual variation in DNA repair capacity and cancer risk are driven, at least in part, by variation in immune function, but this idea is underexplored. In this review we present an overview of the current understanding of the links between cancer risk and both inter-individual variation in DNA repair capacity and inter-individual variation in immune function. We discuss factors that play a role in both types of variability, including age, lifestyle, and environmental exposures. In conclusion, we propose a research paradigm that incorporates functional studies of both genome integrity and the immune system to predict cancer risk and lay the groundwork for personalized prevention.

Clinical application and prospect of MRD evaluation in lung cancer based on ctDNA level: A review

Lung cancer is one of the most malignant cancers in China with a rising incidence rate. Despite the fact that surgical treatment is the only possible cure for lung cancer, its long-term efficacy is compromised by the high level of postoperative local recurrence rate. Minimal residual disease is the leading cause of tumor recurrence, yet the suggested combination of clinical, radiological and serological (carcinoembryonic antigen) tests fails to reveal the underlying residual tissue in all stage I-III lung cancer cases, which makes tumor recurrence surveillance timely. Through monitoring circulating tumor DNA, the minimal residual disease level can be accessed and provide guidance for more precise postoperative personalized treatment, and its scientific feasibility can revolutionize lung cancer therapy. In the present review we summarized the progress of circulating tumor DNA in lung cancer minimal residual disease detection and discussed its application value in guiding precise treatment of lung cancer.

Clinical Significance of Clonal Hematopoiesis of Indeterminate Potential in Hematology and Cardiovascular Disease

Liquid profiling uses circulating tumor DNA (ctDNA) for minimal invasive tumor mutational profiling from peripheral blood. The presence of somatic mutations in peripheral blood cells without further evidence of a hematologic neoplasm defines clonal hematopoiesis of indeterminate potential (CHIP). CHIP-mutations can be found in the cell-free DNA (cfDNA) of plasma, are a potential cause of false positive results in liquid profiling, and thus limit its usage in screening settings. Various strategies are in place to mitigate the effect of CHIP on the performance of ctDNA assays, but the detection of CHIP also represents a clinically significant incidental finding. The sequelae of CHIP comprise the risk of progression to a hematologic neoplasm including therapy-related myeloid neoplasms. While the hematological risk increases with the co-occurrence of unexplained blood count abnormalities, a number of non-hematologic diseases have independently been associated with CHIP. In particular, CHIP represents a major risk factor for cardiovascular disease such as atherosclerosis or heart failure. The management of CHIP requires an interdisciplinary setting and represents a new topic in the field of cardio-oncology. In the future, the information on CHIP may be taken into account for personalized therapy of cancer patients.

Clonal hematopoiesis: Mutation-specific adaptation to environmental change

Clonal hematopoiesis of indeterminate potential (CHIP) describes a widespread expansion of genetically variant hematopoietic cells that increases exponentially with age and is associated with increased risks of cancers, cardiovascular disease, and other maladies. Here, we discuss how environmental contexts associated with CHIP, such as old age, infections, chemotherapy, or cigarette smoking, alter tissue microenvironments to facilitate the selection and expansion of specific CHIP mutant clones. Further, we consider major remaining gaps in knowledge, including intrinsic effects, clone size thresholds, and factors affecting clonal competition, that will determine future application of this field in transplant and preventive medicine.

Current and Developing Liquid Biopsy Techniques for Breast Cancer

Breast cancer is the most commonly diagnosed cancer and leading cause of cancer mortality among woman worldwide. The techniques of diagnosis, prognosis, and therapy monitoring of breast cancer are critical. Current diagnostic techniques are mammography and tissue biopsy; however, they have limitations. With the development of novel techniques, such as personalized medicine and genetic profiling, liquid biopsy is emerging as the less invasive tool for diagnosing and monitoring breast cancer. Liquid biopsy is performed by sampling biofluids and extracting tumor components, such as circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), cell-free mRNA (cfRNA) and microRNA (miRNA), proteins, and extracellular vehicles (EVs). In this review, we summarize and focus on the recent discoveries of tumor components and biomarkers applied in liquid biopsy and novel development of detection techniques, such as surface-enhanced Raman spectroscopy (SERS) and microfluidic devices.

Clonal Hematopoiesis Analyses in Clinical, Epidemiologic, and Genetic Aging Studies to Unravel Underlying Mechanisms of Age-Related Dysfunction in Humans

Aging is characterized by increased mortality, functional decline, and exponential increases in the incidence of diseases such as cancer, stroke, cardiovascular disease, neurological disease, respiratory disease, etc. Though the role of aging in these diseases is widely accepted and considered to be a common denominator, the underlying mechanisms are largely unknown. A significant age-related feature observed in many population cohorts is somatic mosaicism, the detectable accumulation of somatic mutations in multiple cell types and tissues, particularly those with high rates of cell turnover (e.g., skin, liver, and hematopoietic cells). Somatic mosaicism can lead to the development of cellular clones that expand with age in otherwise normal tissues. In the hematopoietic system, this phenomenon has generally been referred to as "clonal hematopoiesis of indeterminate potential" (CHIP) when it applies to a subset of clones in which mutations in driver genes of hematologic malignancies are found. Other mechanisms of clonal hematopoiesis, including large chromosomal alterations, can also give rise to clonal expansion in the absence of conventional CHIP driver gene mutations. Both types of clonal hematopoiesis (CH) have been observed in studies of animal models and humans in association with altered immune responses, increased mortality, and disease risk. Studies in murine models have found that some of these clonal events are involved in abnormal inflammatory and metabolic changes, altered DNA damage repair and epigenetic changes. Studies in long-lived individuals also show the accumulation of somatic mutations, yet at this advanced age, carriership of somatic mutations is no longer associated with an increased risk of mortality. While it remains to be elucidated what factors modify this genotype-phenotype association, i.e., compensatory germline genetics, cellular context of the mutations, protective effects to diseases at exceptional age, it points out that the exceptionally long-lived are key to understand the phenotypic consequences of CHIP mutations. Assessment of the clinical significance of somatic mutations occurring in blood cell types for age-related outcomes in human populations of varied life and health span, environmental exposures, and germline genetic risk factors will be valuable in the development of personalized strategies tailored to specific somatic mutations for healthy aging.

Maladaptive trained immunity and clonal hematopoiesis as potential mechanistic links between periodontitis and inflammatory comorbidities

Periodontitis is bidirectionally associated with systemic inflammatory disorders. The prevalence and severity of this oral disease and linked comorbidities increases with aging. Here, we review two newly emerged concepts, trained innate immunity (TII) and clonal hematopoiesis of indeterminate potential (CHIP), which together support a potential hypothesis on how periodontitis affects and is affected by comorbidities and why the susceptibility to periodontitis and comorbidities increases with aging. Given that chronic diseases are largely triggered by the action of inflammatory immune cells, modulation of their bone marrow precursors, the hematopoietic stem and progenitor cells (HSPCs), may affect multiple disorders that emerge as comorbidities. Such alterations in HSPCs can be mediated by TII and/or CHIP, two non-mutually exclusive processes sharing a bias for enhanced myelopoiesis and production of innate immune cells with heightened proinflammatory potential. TII is a state of elevated immune responsiveness based on innate immune (epigenetic) memory. Systemic inflammation can initiate TII in the bone marrow via sustained rewiring of HSPCs, which thereby display a skewing toward the myeloid lineage, resulting in generation of hyper-reactive or "trained" myeloid cells. CHIP arises from aging-related somatic mutations in HSPCs, which confer a survival and proliferation advantage to the mutant HSPCs and give rise to an outsized fraction of hyper-inflammatory mutant myeloid cells in the circulation and tissues. This review discusses emerging evidence that supports the notion that TII and CHIP may underlie a causal and age-related association between periodontitis and comorbidities. A holistic mechanistic understanding of the periodontitis-systemic disease connection may offer novel diagnostic and therapeutic targets for treating inflammatory comorbidities.

The Minimal Residual Disease Using Liquid Biopsies in Hematological Malignancies

The study of cell-free DNA (cfDNA) and other peripheral blood components (known as "liquid biopsies") is promising, and has been investigated especially in solid tumors. Nevertheless, it is increasingly showing a greater utility in the diagnosis, prognosis, and response to treatment of hematological malignancies; in the future, it could prevent invasive techniques, such as bone marrow (BM) biopsies. Most of the studies about this topic have focused on B-cell lymphoid malignancies; some of them have shown that cfDNA can be used as a novel way for the diagnosis and minimal residual monitoring of B-cell lymphomas, using techniques such as next-generation sequencing (NGS). In myelodysplastic syndromes, multiple myeloma, or chronic lymphocytic leukemia, liquid biopsies may allow for an interesting genomic representation of the tumor clones affecting different lesions (spatial heterogeneity). In acute leukemias, it can be helpful in the monitoring of the early treatment response and the prediction of treatment failure. In chronic lymphocytic leukemia, the evaluation of cfDNA permits the definition of clonal evolution and drug resistance in real time. However, there are limitations, such as the difficulty in obtaining sufficient circulating tumor DNA for achieving a high sensitivity to assess the minimal residual disease, or the lack of standardization of the method, and clinical studies, to confirm its prognostic impact. This review focuses on the clinical applications of cfDNA on the minimal residual disease in hematological malignancies.

Mutant PPM1D- and TP53-Driven Hematopoiesis Populates the Hematopoietic Compartment in Response to Peptide Receptor Radionuclide Therapy

PURPOSE

Hematologic toxic effects of peptide receptor radionuclide therapy (PRRT) can be permanent. Patients with underlying clonal hematopoiesis (CH) may be more inclined to develop hematologic toxicity after PRRT. However, this association remains understudied.

MATERIALS AND METHODS

We evaluated pre- and post-PRRT blood samples of patients with neuroendocrine tumors. After initial screening, 13 cases of interest were selected. Serial blood samples were obtained on 4 of 13 patients. Genomic DNA was analyzed using a 100-gene panel. A variant allele frequency cutoff of 1% was used to call CH.

RESULT

Sixty-two percent of patients had CH at baseline. Persistent cytopenias were noted in 64% (7 of 11) of the patients. Serial sample analysis demonstrated that PRRT exposure resulted in clonal expansion of mutant DNA damage response genes (TP53, CHEK2, and PPM1D) and accompanying cytopenias in 75% (3 of 4) of the patients. One patient who had a normal baseline hemogram and developed persistent cytopenias after PRRT exposure showed expansion of mutant PPM1D (variant allele frequency increased to 20% after exposure from < 1% at baseline). In the other two patients, expansion of mutant TP53, CHEK2, and PPM1D clones was also noted along with cytopenia development.

CONCLUSION

The shifts in hematopoietic clonal dynamics in our study were accompanied by emergence and persistence of cytopenias. These cytopenias likely represent premalignant state, as PPM1D-, CHEK2-, and TP53-mutant clones by themselves carry a high risk for transformation to therapy-related myeloid neoplasms. Future studies should consider CH screening and longitudinal monitoring as a key risk mitigation strategy for patients with neuroendocrine tumors receiving PRRT.

Molecular Minimal Residual Disease Detection in Acute Myeloid Leukemia

Initial induction chemotherapy to eradicate the bulk of acute myeloid leukemia (AML) cells results in complete remission (CR) in the majority of patients. However, leukemic cells persisting in the bone marrow below the morphologic threshold remain unaffected and have the potential to proliferate and re-emerge as AML relapse. Detection of minimal/measurable residual disease (MRD) is a promising prognostic marker for AML relapse as it can assess an individual patients' risk profile and evaluate their response to treatment. With the emergence of molecular techniques, such as next generation sequencing (NGS), a more sensitive assessment of molecular MRD markers is available. In recent years, the detection of MRD by molecular assays and its association with AML relapse and survival has been explored and verified in multiple studies. Although most studies show that the presence of MRD leads to a worse clinical outcome, molecular-based methods face several challenges including limited sensitivity/specificity, and a difficult distinction between mutations that are representative of AML rather than clonal hematopoiesis. This review describes the studies that have been performed using molecular-based assays for MRD detection in the context of other MRD detection approaches in AML, and discusses limitations, challenges and opportunities.

Myelodysplastic Syndromes and Metabolism

Myelodysplastic syndromes (MDS) are acquired clonal stem cell disorders exhibiting ineffective hematopoiesis, dysplastic cell morphology in the bone marrow, and peripheral cytopenia at early stages; while advanced stages carry a high risk for transformation into acute myeloid leukemia (AML). Genetic alterations are integral to the pathogenesis of MDS. However, it remains unclear how these genetic changes in hematopoietic stem and progenitor cells (HSPCs) occur, and how they confer an expansion advantage to the clones carrying them. Recently, inflammatory processes and changes in cellular metabolism of HSPCs and the surrounding bone marrow microenvironment have been associated with an age-related dysfunction of HSPCs and the emergence of genetic aberrations related to clonal hematopoiesis of indeterminate potential (CHIP). The present review highlights the involvement of metabolic and inflammatory pathways in the regulation of HSPC and niche cell function in MDS in comparison to healthy state and discusses how such pathways may be amenable to therapeutic interventions.

Inflammatory Modulation of Hematopoiesis: Linking Trained Immunity and Clonal Hematopoiesis with Chronic Disorders

Inflammation-adapted hematopoietic stem and progenitor cells (HSPCs) have long been appreciated as key drivers of emergency myelopoiesis, thereby enabling the bone marrow to meet the elevated demand for myeloid cell generation under various stress conditions, such as systemic infection, inflammation, or myelosuppressive insults. In recent years, HSPC adaptations were associated with potential involvement in the induction of long-lived trained immunity and the emergence of clonal hematopoiesis of indeterminate potential (CHIP). Whereas trained immunity has context-dependent effects, protective in infections and tumors but potentially detrimental in chronic inflammatory diseases, CHIP increases the risk for hematological neoplastic disorders and cardiometabolic pathologies. This review focuses on the inflammatory regulation of HSPCs in the aforementioned processes and discusses how modulation of HSPC function could lead to novel therapeutic interventions. Expected final online publication date for the Annual Review of Physiology, Volume 84 is February 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Is There a Causal Link Between Periodontitis and Cardiovascular Disease? A Concise Review of Recent Findings

There is substantial evidence in support of an association between periodontitis and cardiovascular disease. The most important open question related to this association is causality. This article revisits the question of causality by reviewing intervention studies and systematic reviews and meta analyses published in the last 3 years. Where are we now in answering this question? Whilst systematic reviews and epidemiological studies continue to support an association between the diseases, intervention studies fall short in determining causality. There is a dearth of good-quality, blinded randomised control trials with cardiovascular disease outcomes. Most studies use surrogate markers/biomarkers for endpoints, and this is problematic as they may not be reflective of cardiovascular disease status. This review further highlights another issue with surrogate markers/biomarkers: the potential for collider bias. Ethical considerations surrounding nontreatment have led to calls for a well-annotated database containing in-depth dental health data. Finally, a relatively new and important risk factor for cardiovascular disease, clonal haematopoiesis of indeterminate potential, is discussed. Clonal haematopoiesis of indeterminate potential increases cardiovascular risk by more than 40%, and inflammation is a contributing factor. The impact of periodontal disease on this emerging risk factor has yet to be explored. Although the question of causality in the association between periodontal disease and cardiovascular disease remains unanswered, the importance of good oral health in maintaining good heart health is reiterated.

Is Hematopoietic Clonality of Indetermined Potential a Risk Factor for Pulmonary Embolism?

Background  Unprovoked pulmonary embolism (uPE) is a severe and frequent condition. Identification of new risk factors is mandatory to identify patients that would benefit from a long-term treatment. Clonal hematopoiesis of indeterminate potential (CHIP) is defined by the acquisition of somatic mutations that drive clonal expansion in the absence of cytopenia. Its prevalence is estimated of 5% in the population above 65 years. Since inflammation and endothelial dysfunction may share a pathophysiological pathway(1), we hypothesized that CHIP, may be a risk factor for uPE.

Methods  We conducted a pilot retrospective observational study. Patients with iPE between 18 to 65 years old were included. PE was considered as unprovoked, when no transient nor persistant risk factor was present and when thrombophilia testing was negative. We excluded documented atherosclerosis, personal or familial history of VTE and presence of cytopenias. CHIP proportion in uPE patients were analyzed using next generation sequencing of the coding sequence of a custom panel composed by DNMT3A, ASXL1, SF3B1, TET2 and TP 53 .

Results  Upon 61 patients with uPE consecutively included, a total of 19 somatic mutations were found in 12 patients (20%) IC95% [10 - 20]. 15 mutations were found in DNMT3A gene, 3 in ASXL1 and one in TET2 . There was no diference in terms of age, PE location, DVT presence and risk stratification in CHIP carriers and non carriers.

Conclusion  We report for the first time, the presence of high rates of CHIP in patients presenting with uPE. Thus, CHIP may be a new risk factor for VTE. These results need to be confirmed in an ongoing prospective case-control study including more patients and using a more diverse gene panel to better determine CHIP incidence in uPE.

Chronic infection drives Dnmt3a-loss-of-function clonal hematopoiesis via IFNγ signaling

Age-related clonal hematopoiesis (CH) is a risk factor for malignancy, cardiovascular disease, and all-cause mortality. Somatic mutations in DNMT3A are drivers of CH, but decades may elapse between the acquisition of a mutation and CH, suggesting that environmental factors contribute to clonal expansion. We tested whether infection provides selective pressure favoring the expansion of Dnmt3a mutant hematopoietic stem cells (HSCs) in mouse chimeras. We created Dnmt3a-mosaic mice by transplanting Dnmt3a-/- and WT HSCs into WT mice and observed the substantial expansion of Dnmt3a-/- HSCs during chronic mycobacterial infection. Injection of recombinant IFNγ alone was sufficient to phenocopy CH by Dnmt3a-/- HSCs upon infection. Transcriptional and epigenetic profiling and functional studies indicate reduced differentiation associated with widespread methylation alterations, and reduced secondary stress-induced apoptosis accounts for Dnmt3a-/- clonal expansion during infection. DNMT3A mutant human HSCs similarly exhibit defective IFNγ-induced differentiation. We thus demonstrate that IFNγ signaling induced during chronic infection can drive DNMT3A-loss-of-function CH.

Incidental findings from cancer next generation sequencing panels

Next-generation sequencing (NGS) technologies have facilitated multi-gene panel (MGP) testing to detect germline DNA variants in hereditary cancer patients. This sensitive technique can uncover unexpected, non-germline incidental findings indicative of mosaicism, clonal hematopoiesis (CH), or hematologic malignancies. A retrospective chart review was conducted to identify cases of incidental findings from NGS-MGP testing. Inclusion criteria included: 1) multiple pathogenic variants in the same patient; 2) pathogenic variants at a low allele fraction; and/or 3) the presence of pathogenic variants not consistent with family history. Secondary tissue analysis, complete blood count (CBC) and medical record review were conducted to further delineate the etiology of the pathogenic variants. Of 6060 NGS-MGP tests, 24 cases fulfilling our inclusion criteria were identified. Pathogenic variants were detected in TP53, ATM, CHEK2, BRCA1 and APC. 18/24 (75.0%) patients were classified as CH, 3/24 (12.5%) as mosaic, 2/24 (8.3%) related to a hematologic malignancy, and 1/24 (4.2%) as true germline. We describe a case-specific workflow to identify and interpret the nature of incidental findings on NGS-MGP. This workflow will provide oncology and genetic clinics a practical guide for the management and counselling of patients with unexpected NGS-MGP findings.

Telomeres: New players in immune-mediated inflammatory diseases?

Telomeres are repetitive DNA sequences located at the ends of linear chromosomes that preserve the integrity and stability of the genome. Telomere dysfunctions due to short telomeres or altered telomere structures can ultimately lead to replicative cellular senescence and chromosomal instability, both mechanisms being hallmarks of ageing. Chronic inflammation, oxidative stress and finally telomere length (TL) dynamics have been shown to be involved in various age-related non-communicable diseases (NCDs). Immune-mediated inflammatory diseases (IMIDs), including affections such as inflammatory bowel disease, psoriasis, rheumatoid arthritis, spondyloarthritis and uveitis belong to this group of age-related NCDs. Although in recent years, we have witnessed the emergence of studies in the literature linking these IMIDs to TL dynamics, the causality between these diseases and telomere attrition is still unclear and controversial. In this review, we provide an overview of available studies on telomere dynamics and discuss the utility of TL measurements in immune-mediated inflammatory diseases.

Myelodysplastic Syndromes in the Postgenomic Era and Future Perspectives for Precision Medicine

Simple Summary

With demographic ageing, improved cancer survivorship and increased diagnostic sensitivity, incident cases of patients with Myelodysplastic Syndromes (MDS) are continuously rising, leading to a relevant impact on health care resources. Disease heterogeneity and various comorbidities are challenges for the management of the generally elderly patients. Therefore, experienced physicians and multidisciplinary teams should be involved in the establishment of the correct diagnosis, risk-assessment and personalized treatment plan. Next-generation sequencing allows for early detection of clonal hematopoiesis and monitoring of clonal evolution, but also poses new challenges for its appropriate use. At present, allogeneic hematopoietic stem cell transplantation remains the only curative treatment option for a minority of fit MDS patients. All others receive palliative treatment and will eventually progress, having an unmet need for novel therapies. Targeting compounds are in prospect for precision medicine, however, abrogation of clonal evolution to acute myeloid leukemia remains actually out of reach.

Abstract

Myelodysplastic syndromes (MDS) represent a heterogeneous group of clonal disorders caused by sequential accumulation of somatic driver mutations in hematopoietic stem and progenitor cells (HSPCs). MDS is characterized by ineffective hematopoiesis with cytopenia, dysplasia, inflammation, and a variable risk of transformation into secondary acute myeloid leukemia. The advent of next-generation sequencing has revolutionized our understanding of the genetic basis of the disease. Nevertheless, the biology of clonal evolution remains poorly understood, and the stochastic genetic drift with sequential accumulation of genetic hits in HSPCs is individual, highly dynamic and hardly predictable. These continuously moving genetic targets pose substantial challenges for the implementation of precision medicine, which aims to maximize efficacy with minimal toxicity of treatments. In the current postgenomic era, allogeneic hematopoietic stem cell transplantation remains the only curative option for younger and fit MDS patients. For all unfit patients, regeneration of HSPCs stays out of reach and all available therapies remain palliative, which will eventually lead to refractoriness and progression. In this review, we summarize the recent advances in our understanding of MDS pathophysiology and its impact on diagnosis, risk-assessment and disease monitoring. Moreover, we present ongoing clinical trials with targeting compounds and highlight future perspectives for precision medicine.

Clonal Hematopoiesis of Indeterminate Potential as a Novel Risk Factor for Donor-Derived Leukemia

Hematopoietic stem cell transplantation (HSCT) is a critical treatment modality for many hematological and non-hematological diseases that is being extended to treat older individuals. However, recent studies show that clonal hematopoiesis of indeterminate potential (CHIP), a common, asymptomatic condition characterized by the expansion of age-acquired somatic mutations in blood cell lineages, may be a risk factor for the development of donor-derived leukemia (DDL), unexplained cytopenias, and chronic graft-versus-host disease. CHIP may contribute to the pathogenesis of these significant transplant complications via various cell-autonomous and non-cell-autonomous mechanisms, and the clinical presentation of DDL may be broader than anticipated. A more comprehensive understanding of the contributions of CHIP to DDL may have important implications for the screening of donors and will improve the safety of HSCT. The objective of this review is to discuss studies linking DDL and CHIP and to explore potential mechanisms by which CHIP may contribute to DDL.

Reference intervals of red blood cell parameters and platelet count for healthy adults in Japan

Although it is known that red blood cell (RBC) parameters and platelet count depend on ethnicity and sex, their reference intervals in healthy Asian populations are limited. The aim of this study was to establish reference intervals for RBC parameters and platelet count for healthy adults in Japan. A total of 750 healthy adults (447 women and 303 men; median age 40 years (18-67 years) at seven Japanese centers who participated in regular medical checkups entered this study. Their RBC parameters and platelet count were measured using automated hematocytometers. The reference intervals of the RBC parameters and platelet count according to sex in healthy adults were determined. There was an age-specific decrease in RBC counts and an age-specific increase in mean corpuscular volume in men. This study emphasizes the need to consider sex and age in the clinical use of reference intervals of RBC parameters.

Stem cell donors should be screened for CHIP

This article has a companion Counterpoint by Gibson and Lindsley.

To portray clonal evolution in blood cancer, count your stem cells

Clonal evolution, the process of expansion and diversification of mutated cells, plays an important role in cancer development, resistance, and relapse. Although clonal evolution is most often conceived of as driven by natural selection, recent studies uncovered that neutral evolution shapes clonal evolution in a significant proportion of solid cancers. In hematological malignancies, the interplay between neutral evolution and natural selection is also disputed. Because natural selection selects cells with a greater fitness, providing a growth advantage to some cells relative to others, the architecture of clonal evolution serves as indirect evidence to distinguish natural selection from neutral evolution and has been associated with different prognoses for the patient. Linear architecture, when the new mutant clone grows within the previous one, is characteristic of hematological malignancies and is typically interpreted as being driven by natural selection. Here, we discuss the role of natural selection and neutral evolution in the production of linear clonal architectures in hematological malignancies. Although it is tempting to attribute linear evolution to natural selection, we argue that a lower number of contributing stem cells accompanied by genetic drift can also result in a linear pattern of evolution, as illustrated by simulations of clonal evolution in hematopoietic stem cells. The number of stem cells contributing to long-term clonal evolution is not known in the pathological context, and we advocate that estimating these numbers in the context of cancer and aging is crucial to parsing out neutral evolution from natural selection, 2 processes that require different therapeutic strategies.

Design, implementation and clinical utility of next generation sequencing in myeloid malignancies: acute myeloid leukaemia and myelodysplastic syndrome

Next generation sequencing (NGS) based technology has contributed enormously to our understanding of the biology of myeloid malignancies including acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS). Assessment of clinically important mutations by NGS is a powerful tool to define diagnosis, determine prognostic risk, monitor measurable residual disease and uncover predictive mutational markers/therapeutic targets, and is now a routine component in the workup and monitoring of haematological disorders. There are many technical challenges in the design, implementation, analysis and reporting of NGS based results, and expert interpretation is essential. It is vital to distinguish relevant somatic disease associated mutations from those that are known polymorphisms, rare germline variants and clonal haematopoiesis of indeterminate potential (CHIP) associated variants. This review highlights and addresses the technical and biological challenges that should be considered before the implementation of NGS based testing in diagnostic laboratories and seeks to outline the essential and expanding role NGS plays in myeloid malignancies. Broad aspects of NGS panel design and reporting including inherent technological, biological and economic considerations are covered, following which the utility of NGS based testing in AML and MDS are discussed. In current practice, patient care is now strongly shaped by the results of NGS assessment and is considered a vital piece of the puzzle for clinicians as they manage these complex haematological disorders.

How I treat cancer-associated anemia

Despite increasing use of targeted therapies to treat cancer, anemia remains a common complication of cancer therapy. Physician concerns about the safety of intravenous (IV) iron products and erythropoiesis-stimulating agents (ESAs) have resulted in many patients with cancer receiving no or suboptimal anemia therapy. In this article, we present 4 patient cases that illustrate both common and complex clinical scenarios. We first present a review of erythropoiesis and then describe our approach to cancer-associated anemia by identifying the contributing causes before selecting specific treatments. We summarize clinical trial data affirming the safety and efficacy of currently available IV iron products used to treat cancer-associated anemia and illustrate how we use commonly available laboratory tests to assess iron status during routine patient management. We compare adverse event rates associated with IV iron vs red cell transfusion and discuss using first-line IV iron monotherapy to treat anemic patients with cancer, which decreases the need for ESAs. A possible mechanism behind ESA-induced tumor progression is discussed. Finally, we review the potential of novel therapies such as ascorbic acid, prolyl hydroxylase inhibitors, activin traps, hepcidin, and bone morphogenetic protein antagonists in treating cancer-associated anemia.

When Should We Think of Myelodysplasia or Bone Marrow Failure in a Thrombocytopenic Patient? A Practical Approach to Diagnosis

Thrombocytopenia can arise from various conditions, including myelodysplastic syndromes (MDS) and bone marrow failure (BMF) syndromes. Meticulous assessment of the peripheral blood smear, identification of accompanying clinical conditions, and characterization of the clinical course are important for initial assessment of unexplained thrombocytopenia. Increased awareness is required to identify patients with suspected MDS or BMF, who are in need of further investigations by a step-wise approach. Bone marrow cytomorphology, histopathology, and cytogenetics are complemented by myeloid next-generation sequencing (NGS) panels. Such panels are helpful to distinguish reactive cytopenia from clonal conditions. MDS are caused by mutations in the hematopoietic stem/progenitor cells, characterized by cytopenia and dysplasia, and an inherent risk of leukemic progression. Aplastic anemia (AA), the most frequent acquired BMF, is immunologically driven and characterized by an empty bone marrow. Diagnosis remains challenging due to overlaps with other hematological disorders. Congenital BMF, certainly rare in adulthood, can present atypically with thrombocytopenia and can be misdiagnosed. Analyses for chromosome fragility, telomere length, and germline gene sequencing are needed. Interdisciplinary expert teams contribute to diagnosis, prognostication, and choice of therapy for patients with suspected MDS and BMF. With this review we aim to increase the awareness and provide practical approaches for diagnosis of these conditions in suspicious cases presenting with thrombocytopenia.

From Clonal Hematopoiesis to Therapy-Related Myeloid Neoplasms: The Silent Way of Cancer Progression

Simple Summary

In the last decades the improved management of cancer patients and the overall prolonged life expectancy contributed to the increased number of patients at risk of late clonal events such as therapy-related myeloid neoplasms (t-MN). The discovery of clonal hematopoiesis of indeterminate potential (CHIP) in normal individuals has shed light on the pathophysiologic mechanism behind the process of myeloid evolution, defining CHIP carriers at higher risk of progression. Moreover, different patterns of clonal evolution have been identified in case of t-MN development after anti-cancer treatment exposure. The growing body of evidence in this field allowed the creation of dedicated cancer survivorship programs and “CHIP-Clinics” in order to specifically address the issue of CHIP in patients undergoing anti-cancer treatment and develop measure of early detection possibly guiding tumor surveillance.

Abstract

Clonal hematopoiesis (CH) has been recognized as a predisposing factor for the development of myeloid malignancies. Its detection has been reported at different frequencies across studies, based on the type of genome scanning approach used and the population studied, but the latest insights recognize its virtual ubiquitous presence in older individuals. The discovery of CH in recent years paved the way for a shift in the paradigm of our understanding of the biology of therapy-related myeloid malignancies (t-MNs). Indeed, we moved from the concept of a treatment-induced lesion to a model where CH precedes the commencement of any cancer-related treatment in patients who subsequently develop a t-MN. Invariant patterns of genes seem to contribute to the arising of t-MN cases, with differences regarding the type of treatment received. Here, we review the principal studies concerning CH, the relationship with myeloid progression and the mechanisms of secondary t-MN development.

Mechanistic Biomarkers Informative of Both Cancer and Cardiovascular Disease: JACC State-of-the-Art Review

Cardiovascular disease (CVD) and cancer are leading causes of morbidity and mortality worldwide. Although conventionally managed as separate disease processes, recent research has lent insight into compelling commonalities between CVD and cancer, including shared mechanisms for disease development and progression. In this review, the authors discuss several pathophysiological processes common to both CVD and cancer, such as inflammation, resistance to cell death, cellular proliferation, neurohormonal stress, angiogenesis, and genomic instability, in an effort to understand common mechanisms of both disease states. In particular, the authors highlight key circulating and genomic biomarkers associated with each of these processes, as well as their associations with risk and prognosis in both cancer and CVD. The purpose of this state-of-the-art review is to further our understanding of the potential mechanisms underlying cancer and CVD by contextualizing pathways and biomarkers common to both diseases.

Cytogenetic and molecular aberrations and worse outcome for male patients in systemic mastocytosis

In systemic mastocytosis (SM), the clinical features and survival vary greatly. Patient-related factors determining the outcome in SM are largely unknown. Methods: We examined the impact of sex on the clinical features, progression-free survival (PFS), and overall survival (OS) in 3403 patients with mastocytosis collected in the registry of the European Competence Network on Mastocytosis (ECNM). The impact of cytogenetic and molecular genetic aberrations on sex differences was analyzed in a subset of patients. Results: Of all patients enrolled, 55.3% were females. However, a male predominance was found in a subset of advanced SM (AdvSM) patients, namely SM with an associated hematologic neoplasm (SM-AHN, 70%; p < 0.001). Correspondingly, organomegaly (male: 23% vs. female: 13%, p = 0.007) was more, whereas skin involvement (male: 71% vs. female: 86%, p = 0.001) was less frequent in males. In all patients together, OS (p < 0.0001) was significantly inferior in males, and also within the WHO sub-categories indolent SM, aggressive SM (ASM) and SM-AHN. PFS was significantly (p = 0.0002) worse in males when all patients were grouped together; due to low numbers of events, this significance persisted only in the subcategory smoldering SM. Finally, prognostically relevant cytogenetic abnormalities (10% vs. 5%, p = 0.006) or molecular aberrations (SRSF2/ASXL1/RUNX1 profile; 63% vs. 40%, p = 0.003) were more frequently present in males. Conclusions: Male sex has a major impact on clinical features, disease progression, and survival in mastocytosis. Male patients have an inferior survival, which seems related to the fact that they more frequently develop a multi-mutated AdvSM associated with a high-risk molecular background.

Assessment of technical heterogeneity among diagnostic tests to detect germline risk variants for hematopoietic malignancies

PURPOSE

To determine the degree of testing consistency among commercially available diagnostic assays for hereditary hematopoietic malignancies (HHMs).

METHODS

Next-generation sequencing assays designed for the diagnosis of HHMs were studied to determine which genes were sequenced, their ability to detect variant types relevant for HHMs, and clinical-grade characteristics such as price, turnaround time, and tissue types accepted.

RESULTS

Commercial assays varied in price (USD 250-4702), number of genes sequenced (12-73), and average turnaround time (14-42 days). A number of nongermline tissue types were accepted despite the tests being designed for germline diagnostic purposes. Multiple genes with well-characterized roles in HHM pathogenesis were omitted from more than one-third of panels intended for the evaluation of HHMs. Only 4 of 82 genes were consistently covered across all HHM diagnostic panels. The assays were highly variable in their sensitivity for structural alterations relevant to HHMs, such as copy-number variants.

CONCLUSION

A high degree of diagnostic heterogeneity exists among commercially available HHM diagnostic assays. Many of these assays are incapable of detecting the full spectrum of HHM-associated variants, leaving patients vulnerable to the consequences of underdiagnosis, missed opportunities for screening, and the potential for donor-derived malignancies.

Clonal Hematopoiesis Before, During, and After Human Spaceflight

Clonal hematopoiesis (CH) occurs when blood cells harboring an advantageous mutation propagate faster than others. These mutations confer a risk for hematological cancers and cardiovascular disease. Here, we analyze CH in blood samples from a pair of twin astronauts over 4 years in bulk and fractionated cell populations using a targeted CH panel, linked-read whole-genome sequencing, and deep RNA sequencing. We show CH with distinct mutational profiles and increasing allelic fraction that includes a high-risk, TET2 clone in one subject and two DNMT3A mutations on distinct alleles in the other twin. These astronauts exhibit CH almost two decades prior to the mean age at which it is typically detected and show larger shifts in clone size than age-matched controls or radiotherapy patients, based on a longitudinal cohort of 157 cancer patients. As such, longitudinal monitoring of CH may serve as an important metric for overall cancer and cardiovascular risk in astronauts.

Trinchant et al. examined twin astronauts for clonal hematopoiesis (CH). Some high-risk CH clones (TET2 and DNMT3A) were observed two decades before expected, with TET2 decreasing in spaceflight and elevating later post flight. Thus, CH is an important metric for overall cancer and cardiovascular risk in astronauts.

Cigarette Smoke Exposure in Mice using a Whole-Body Inhalation System

Close to 14% of adults in the United States were reported to smoke cigarettes in 2018. The effects of cigarette smoke (CS) on lungs and cardiovascular diseases have been widely studied, however, the impact of CS in other tissues and organs such as blood and bone marrow remain incompletely defined. Finding the appropriate system to study the effects of CS in rodents can be prohibitively expensive and require the purchase of commercially available systems. Thus, we set out to build an affordable, reliable, and versatile system to study the pathologic effects of CS in mice. This whole-body inhalation exposure system (WBIS) set-up mimics the breathing and puffing of cigarettes by alternating exposure to CS and clean air. Here we show that this do-it-yourself (DIY) system induces airway inflammation and lung emphysema in mice after 4-months of cigarette smoke exposure. The effects of whole-body inhalation (WBI) of CS on hematopoietic stem and progenitor cells (HSPCs) in the bone marrow using this apparatus are also shown.

What to tell your patient with clonal hematopoiesis and why: insights from 2 specialized clinics

Acquired genetic mutations in hematopoietic stem or progenitor cells can lead to clonal expansion and imbalanced blood cell production. Clonal hematopoiesis is exceptionally common with human aging, confers a risk of evolution to overt hematologic malignancy, and increases all-cause mortality and the risk of cardiovascular disease. The degree of risk depends on the specific mutant allele driving clonal expansion, number of mutations, mutant allele burden, and concomitant nongenetic risk factors (eg, hypertension or cigarette smoking). People with clonal hematopoiesis may come to clinical attention in a variety of ways, including during the evaluation of a possible hematologic malignancy, as an incidental discovery during molecular analysis of a nonhematologic neoplasm, after hematopoietic cell transplantation, or as a result of germline testing for inherited variants. Even though the risk of clonal progression or a cardiovascular event in an individual patient with clonal hematopoiesis may be low, the possibility of future clinical consequences may contribute to uncertainty and worry, because it is not yet known how to modify these risks. This review summarizes clinical considerations for patients with clonal hematopoiesis, including important points for hematologists to consider discussing with affected persons who may understandably be anxious about having a mutation in their blood that predisposes them to develop a malignancy, but which is significantly more likely to result in a myocardial infarction or stroke. The increasing frequency with which people with clonal hematopoiesis are discovered and the need for counseling these patients is driving many institutions to create specialized clinics. We describe our own experience with forming such clinics.

Clonal Hematopoiesis of Indeterminate Potential: A Multidisciplinary Challenge in Personalized Hematology

Clonal hematopoiesis of indeterminate potential (CHIP) is a common age-related condition that represents a potential pre-phase of hematologic neoplasm. Next-generation sequencing (NGS) is used to detect and monitor clonal hematopoiesis, and the spectrum of mutations substantially overlaps with that of myeloid neoplasms with DNMT3A, TET2, ASXL1, and JAK2 being the most frequently mutated. While, in general, the risk of progression to an overt myeloid neoplasm is only modest, the progression risk increases in patients with unexplained cytopenia or multiple mutations. In addition, CHIP represents a previously unrecognized major risk factor for atherosclerosis and cardiovascular disease (CVD), including coronary heart disease, degenerative aortic valve stenosis, and chronic heart failure; and a causative role of CHIP in the development of CVD has been demonstrated in vitro and in vivo. The management of patients with CHIP is a rapidly emerging topic in personalized medicine, as NGS has become widely available for clinical medicine. It requires a highly multidisciplinary setting, including hematology/oncology, cardiology, (clinical) pathology, and genetics for individualized guidance. Further research is urgently needed to provide robust evidence for future guidelines and recommendations on the management of patients with CHIP in the era of personalized medicine.

Clinical significance of clonal hematopoiesis in the interpretation of blood liquid biopsy

As the use of next-generation sequencing (NGS) for plasma cell-free DNA (cfDNA) continues to expand in clinical settings, accurate identification of circulating tumor DNA mutations is important to validate its use in the clinical management for cancer patients. Here, we aimed to characterize mutations including clonal hematopoiesis (CH)-related mutations in plasma cfDNA and tumor tissues using the same ultradeep NGS assay and evaluate the clinical significance of CH-related mutations on the interpretation of liquid biopsy results. Ultradeep targeted NGS using Oncomine Pan-Cancer Panel was performed on matched surgically resected tumor tissues, peripheral blood cells (PBCs), and 120 plasma cfDNA samples from 38 colorectal cancer patients. The clinical significance of the CH-related mutations in plasma cfDNA was evaluated by longitudinal monitoring of the postoperative plasma samples. Among the 38 patients, 74 nonsynonymous mutations were identified from tumor tissues and 64 mutations from the preoperative plasma samples. Eleven (17%) of the 64 mutations identified in plasma cfDNA were also detected in PBC DNA and were identified to be CH-related mutations. Overall, 11 of 38 (29%) patients in this cohort harbored at least one CH-related mutation in plasma cfDNA. These CH-related mutations were continuously detected in subsequent postoperative plasma samples from three patients which could be misinterpreted as the presence of residual disease or as lack of treatment response. Our results indicated that it is essential to integrate the mutational information of PBCs to differentiate tumor-derived from CH-related mutations in liquid biopsy analysis. This would prevent the misinterpretation of results to avoid misinformed clinical management for cancer patients.