Uncovering perturbations in human hematopoiesis associated with healthy aging and myeloid malignancies at single-cell resolution

Early hematopoiesis is a continuous process in which hematopoietic stem and progenitor cells (HSPCs) gradually differentiate toward specific lineages. Aging and myeloid malignant transformation are characterized by changes in the composition and regulation of HSPCs. In this study, we used single-cell RNA sequencing (scRNA-seq) to characterize an enriched population of human HSPCs obtained from young and elderly healthy individuals.

Based on their transcriptional profile, we identified changes in the proportions of progenitor compartments during aging, and differences in their functionality, as evidenced by gene set enrichment analysis. Trajectory inference revealed that altered gene expression dynamics accompanied cell differentiation, which could explain aging-associated changes in hematopoiesis. Next, we focused on key regulators of transcription by constructing gene regulatory networks (GRNs) and detected regulons that were specifically active in elderly individuals. Using previous findings in healthy cells as a reference, we analyzed scRNA-seq data obtained from patients with myelodysplastic syndrome (MDS) and detected specific alterations of the expression dynamics of genes involved in erythroid differentiation in all patients with MDS such as TRIB2. In addition, the comparison between transcriptional programs and GRNs regulating normal HSPCs and MDS HSPCs allowed identification of regulons that were specifically active in MDS cases such as SMAD1, HOXA6, POU2F2, and RUNX1 suggesting a role of these transcription factors (TFs) in the pathogenesis of the disease.

In summary, we demonstrate that the combination of single-cell technologies with computational analysis tools enable the study of a variety of cellular mechanisms involved in complex biological systems such as early hematopoiesis and can be used to dissect perturbed differentiation trajectories associated with perturbations such as aging and malignant transformation. Furthermore, the identification of abnormal regulatory mechanisms associated with myeloid malignancies could be exploited for personalized therapeutic approaches in individual patients.

The transcription factor DDIT3 is a potential driver of dyserythropoiesis in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are hematopoietic stem cell (HSC) malignancies characterized by ineffective hematopoiesis, with increased incidence in older individuals. Here we analyze the transcriptome of human HSCs purified from young and older healthy adults, as well as MDS patients, identifying transcriptional alterations following different patterns of expression. While aging-associated lesions seem to predispose HSCs to myeloid transformation, disease-specific alterations may trigger MDS development. Among MDS-specific lesions, we detect the upregulation of the transcription factor DNA Damage Inducible Transcript 3 (DDIT3). Overexpression of DDIT3 in human healthy HSCs induces an MDS-like transcriptional state, and dyserythropoiesis, an effect associated with a failure in the activation of transcriptional programs required for normal erythroid differentiation. Moreover, DDIT3 knockdown in CD34⁺ cells from MDS patients with anemia is able to restore erythropoiesis. These results identify DDIT3 as a driver of dyserythropoiesis, and a potential therapeutic target to restore the inefficient erythroid differentiation characterizing MDS patients.

Surgical Outcome and Oncological Survival of Osteofibrous Dysplasia-Like and Classic Adamantinomas: An International Multicenter Study of 318 Cases

BACKGROUND

Osteofibrous dysplasia-like adamantinoma (OFD-AD) and classic adamantinoma (AD) are rare, neoplastic diseases with only limited data supporting current treatment protocols. We believe that our retrospective multicenter cohort study is the largest analysis of patients with adamantinoma to date. The primary purpose of this study was to describe the disease characteristics and evaluate the oncological outcomes. The secondary purpose was to identify risk factors for local recurrence after surgical treatment and propose treatment guidelines.

METHODS

Three hundred and eighteen confirmed cases of OFD-AD and AD for which primary treatment was carried out between 1985 and 2015 were submitted by 22 tertiary bone tumor centers. Proposed clinical risk factors for local recurrence such as size, type, and margins were analyzed using univariable and multivariate Cox regression analysis.

RESULTS

Of the 318 cases, 128 were OFD-AD and 190 were AD. The mean age at diagnosis was 17 years (median, 14.5 years) for OFD-AD and 32 years (median, 28 years) for AD; 53% of the patients were female. The mean tumor size in the OFD-AD and AD groups combined was 7.8 cm, measured histologically. Sixteen percent of the patients sustained a pathological fracture prior to treatment. Local recurrence was recorded in 22% of the OFD-AD cases and 24% of the AD cases. None of the recurrences in the OFD-AD group progressed to AD. Metastatic disease was found in 18% of the AD cases and fatal disease, in 11% of the AD cases. No metastatic or fatal disease was reported in the OFD-AD group. Multivariate Cox regression analysis demonstrated that uncontaminated resection margins (hazard ratio [HR] = 0.164, 95% confidence interval [CI] = 0.092 to 0.290, p < 0.001), pathological fracture (HR = 1.968, 95% CI = 1.076 to 3.600, p = 0.028), and sex (female versus male: HR = 0.535, 95% CI = 0.300 to 0.952, p = 0.033) impacted the risk of local recurrence.

CONCLUSIONS

OFD-AD and AD are parts of a disease spectrum but should be regarded as different entities. Our results support reclassification of OFD-AD into the intermediate locally aggressive category, based on the local recurrence rate of 22% and absence of metastases. In our study, metastatic disease was restricted to the AD group (an 18% rate). We advocate wide resection with uncontaminated margins including bone and involved periosteum for both OFD-AD and AD.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Prognosis and treatment of acrometastases: Observational study of 35 cases treated in a single institution

OBJECTIVE

There is a degree of contradiction in the literature about the primary tumour that is most frequently associated with acrometastases, as well as their prognosis and treatment. The aim of this study is to determine the most frequent location of the acrometastases, the most frequent primary tumour according to its location, and to evaluate the surgical options according to the estimated survival.

METHODS

A retrospective study on patients diagnosed with acrometastases. The primary tumour, as well as the number, location, symptoms and treatment of the acrometastases and survival rate were collected.

RESULTS

35 acrometastases in 21 patients were reviewed: 4 in the upper limbs and 31 in the lower limbs; the tibia was the most frequently affected bone (N=13). The primary tumour that most frequently produced acrometastases in the lower limb was hypernephroma (19%). In the upper limb lung tumour was more frequent (25%). Eleven patients died (52%); 10 of them had concomitant multiple metastases. The mean survival was 42 months from the diagnosis of acrometastases.

CONCLUSION

Acrometastases are more frequently seen in the lower extremities and the most frequent tumour was hypernephroma followed by lung. The treatment of acrometastases depends on the prognosis of the primary tumour, so a multidisciplinary approach is essential. The mean survival in our series did not imply a poorer prognosis for acrometastases, so it is feasible to consider surgical options such as wide resection and reconstruction. A unique acrometastases is a good prognosis signal.

Integrating Morphology and Genetics in the Diagnosis of Cartilage Tumors

Cartilage-forming tumors of bone are a heterogeneous group of tumors with different molecular mechanisms involved. Enchondromas are benign hyaline cartilage-forming tumors of medullary bone caused by mutations in IDH1 or IDH2. Osteochondromas are benign cartilage-capped bony projections at the surface of bone. IDH mutations are also found in dedifferentiated and periosteal chondrosarcoma. A recurrent HEY1-NCOA2 fusion characterizes mesenchymal chondrosarcoma. Molecular changes are increasingly used to improve diagnostic accuracy in chondrosarcomas. Detection of IDH mutations or HEY1-NCOA2 fusions has already proved their immense value, especially on small biopsy specimens or in case of unusual presentation.

Mesenchymal chondrosarcoma: prognostic factors and outcome in 113 patients. A European Musculoskeletal Oncology Society study

BACKGROUND

Mesenchymal chondrosarcoma (MCS) is a distinct, very rare sarcoma with little evidence supporting treatment recommendations.

PATIENTS AND METHODS

Specialist centres collaborated to report prognostic factors and outcome for 113 patients.

RESULTS

Median age was 30 years (range: 11-80), male/female ratio 1.1. Primary sites were extremities (40%), trunk (47%) and head and neck (13%), 41 arising primarily in soft tissue. Seventeen patients had metastases at diagnosis. Mean follow-up was 14.9 years (range: 1-34), median overall survival (OS) 17 years (95% confidence interval (CI): 10.3-28.6). Ninety-five of 96 patients with localised disease underwent surgery, 54 additionally received combination chemotherapy. Sixty-five of 95 patients are alive and 45 progression-free (5 local recurrence, 34 distant metastases, 11 combined). Median progression-free survival (PFS) and OS were 7 (95% CI: 3.03-10.96) and 20 (95% CI: 12.63-27.36) years respectively. Chemotherapy administration in patients with localised disease was associated with reduced risk of recurrence (P=0.046; hazard ratio (HR)=0.482 95% CI: 0.213-0.996) and death (P=0.004; HR=0.445 95% CI: 0.256-0.774). Clear resection margins predicted less frequent local recurrence (2% versus 27%; P=0.002). Primary site and origin did not influence survival. The absence of metastases at diagnosis was associated with a significantly better outcome (P<0.0001). Data on radiotherapy indications, dose and fractionation were insufficiently complete, to allow comment of its impact on outcomes. Median OS for patients with metastases at presentation was 3 years (95% CI: 0-4.25).

CONCLUSIONS

Prognosis in MCS varies considerably. Metastatic disease at diagnosis has the strongest impact on survival. Complete resection and adjuvant chemotherapy should be considered as standard of care for localised disease.

Prognostic factors and outcomes for osteosarcoma: an international collaboration

We aimed to evaluate the prognostic significance of traditional clinical predictors in osteosarcoma through an international collaboration of 10 teams of investigators (2680 patients) who participated. In multivariate models the mortality risk increased with older age, presence of metastatic disease at diagnosis, development of local recurrence when the patient was first seen, use of amputation instead of limb salvage/wide resection, employment of unusual treatments, use of chemotherapeutic regimens other than anthracycline and platinum and use of methotrexate. It was also influenced by the site of the tumour. The risk of metastasis increased when metastatic disease was present at the time the patient was first seen and also increased with use of amputation or unusual treatment combinations or chemotherapy regimens not including anthracycline and platinum. Local recurrence risk was higher in older patients, in those who had local recurrence when first seen and when no anthracycline and platinum were used in chemotherapy. Results were similar when limited to patients seen after 1990 and treated with surgery plus combination chemotherapy. This large-scale international collaboration identifies strong predictors of major clinical outcomes in osteosarcoma.

EULAR/EFORT recommendations for the diagnosis and initial management of patients with acute or recent onset swelling of the knee

Objectives:

The European League Against Rheumatism (EULAR) and the European Federation of National Associations of Orthopaedics and Traumatology (EFORT) have recognised the importance of variation in diagnostic and therapeutic performance across disciplines, have found consensus in starting task forces aiming at achieving diagnostic and therapeutic uniformity, and have identified medical conditions with which representatives of both organisations will frequently be confronted in common clinical practice. The aim of the present work was to establish recommendations for the diagnosis and initial management of patients presenting with acute or recent onset swelling of the knee.

Methods:

The EULAR standard operating procedures for the elaboration and implementation of evidence-based recommendations were followed.

Results:

In all, 11 rheumatologists from 11 countries and 12 orthopaedic surgeons from 7 countries met twice under the leadership of 2 conveners, a clinical epidemiologist and a research fellow. After carefully defining the content and procedures of the task force, research questions were developed, a comprehensive literature search was performed and the results were presented to the entire committee. Subsequently, a set of 10 recommendations was formulated based on evidence from the literature if available, and after discussion and consensus building.

Conclusions:

This is the first combined interdisciplinary project of rheumatologists and orthopaedic surgeons, successfully aiming at achieving consensus in the diagnosis and initial management of patients presenting with acute or recent onset swelling of the knee.

Limb salvage in Ewing's sarcoma of the distal lower extremity

BACKGROUND

Ewing's sarcoma (ES) of the foot and ankle is a rare condition whose treatment is controversial. There are no large series covering this issue. Some authors advise amputation as the "gold standard" treatment. The authors here prsent their experience in limb salvage of fourteen cases of ES in distal lower extremities.

METHODS

The clinical records of fourteen patients affected by ES in ankle or foot were reviewed. Particular attention was paid to followup, functional status, type of treatment, survivorship and histological response to treatment.

RESULTS

Straightforward amputation was employed in just 3 cases of toe location, and another case located in the calcaneum was considered unresectable. Limb salvage was achieved in most patients with tumors in tarsal and metatarsal bones, as well as distal tibia and distal fibula locations. There were no local recurrences of the tumor. All but on patient survived after a minimum follow-up of four years (4 to 22). The function at the last follow-up was excellent or good in 80% of cases of limb salvage, mainly in non-irradiated patients.

CONCLUSIONS

Chemotherapy and resection with reconstruction of the foot yielded excellent results in ES cases. Survivorship of ES in distal locations seems to be better than for proximal ones. High doses of radiotherapy and amputation can be avoided in the treatment of these tumors.

Dedifferentiated chondrosarcoma: prognostic factors and outcome from a European group

BACKGROUND

Dedifferentiated chondrosarcoma has a very poor prognosis. Because of its rarity, there are few large studies of outcome which might identify potential prognostic factors. In particular there remains uncertainty about the value of chemotherapy for this condition.

METHOD

A retrospective study was done using data supplied by members of the European Musculo Skeletal Oncology Society (EMSOS). We obtained data on 337 patients from nine European centres with this rare condition, with details on patients, treatment and outcome which were then analysed in an attempt to identify prognostic features.

RESULTS

The median age was 59 years and there was a slight predominance of males (53%). The most common sites were the femur and pelvis. Twenty-nine percent of patients with a long bone tumour had a pathological fracture. 71 patients (21%) had metastases at the time of diagnosis and these patients had a median survival of 5 months with a 10% chance of survival at 2 years. For the 266 patients without metastases at diagnosis, 254 underwent surgery with 79% having limb salvage. Thirty-one percent of these 266 patients had chemotherapy with 47% of those under 60 receiving it. In this group of 266 patients, overall survival was 28% at 10 years and poor prognostic factors were the presence of a pathological fracture at diagnosis, a pelvic location and increasing age. Local recurrence and overall survival were related to inadequate margins of excision. We did not find that the histological subtype, size of the tumour or the use of chemotherapy significantly affected outcome. For all patients the overall survival was 24% at 5 years.

CONCLUSIONS

The prognosis for patients with dedifferentiated chondrosarcoma remains dismal. Surgery with clear margins remains the principal treatment for this condition. Further use of chemotherapy should be within a trial or treatment protocol.

Periosteal osteosarcoma – a European review of outcome

Periosteal osteosarcoma is a rare primary malignant bone tumour. Treatment is by surgical excision, but controversy remains about the value of chemotherapy. The members of the European Musculo Skeletal Oncology Society (EMSOS) collaborated to produce a dataset of 119 patients. The predominant site for the tumour was the femur, followed by the tibia. All but 2 patients underwent surgery, with 9 requiring amputation and the others having limb salvage. A total of 81 patients had chemotherapy, of whom 50 had neoadjuvant chemotherapy. There was no standard chemotherapy regime, but all patients receiving chemotherapy were given doxorubicin combined with at least one other agent. The overall survival was 89% at 5 years and 83% at 10 years. Eight patients developed local recurrence, of whom 5 died. Survival was related to appearance of local recurrence (P < 0.0001) but no other single factor. The use of chemotherapy was not shown to be a prognostic factor, but was used in two-thirds of the patients in this study.

Limb salvage in bone sarcomas in patients younger than age 10: a 20-year experience

The authors present their experience over the last 20 years in limb salvage procedures of a consecutive series of 40 children under 10 years of age (range 2-10 years) with bone sarcomas. Nineteen were osteogenic sarcomas and 21 were Ewing sarcomas. Only one case, located in the distal phalanx of the toe, was treated by straightforward amputation. Intercalary allografts and Canadell's technique were used to preserve joints whenever possible, and prosthesis or osteoarticular allografts were used when the joint surface was involved. Survival rate in this series was 75%. There were four local recurrences. At the last follow-up (mean 11.2 years, range 5-19 years postop), 90% of the patients preserved their limbs. Eighty percent of the authors' results were excellent or good according to the Musculoskeletal Tumor Society Scale. Limb salvage is a real possibility even in young children with bone sarcomas. The age of the patient itself is not a contraindication for limb salvage.

Bone metastases from osteosarcoma

Bony metastases in patients with osteosarcoma are unusual and normally appear late in the course of the disease. We report our experience with eight such patients, four with solitary and four with multiple metastases. Those with solitary metastases were treated as new tumours with neoadjuvant chemotherapy and surgery. Three remain alive with no evidence of disease at 5, 7 and 8 years follow-up respectively. Histology and response to neoadjuvant chemotherapy was similar in both the primary and metastatic lesions and is a predictive factor of outcome. Those with multiple metastases were treated by palliative measures, and none survived. We conclude that resection of solitary metastases from osteosarcoma after neoadjuvant chemotherapy can be curative.

Osteosarcoma over the age of forty

The European Musculo Skeletal Oncology Society (EMSOS) has carried out a retrospective review of patients over the age of 40 years with osteosarcoma. 481 patients from 12 centres or multicentric groups were included. 42 patients had osteosarcoma arising in Paget's disease, median survival was 9 months. Patients with axial or metastatic tumours also did badly whilst 41 patients with radiation-induced osteosarcoma had a prognosis paralleling conventional osteosarcoma matched for patient age and site of the tumour. 238 patients had high grade non-metastatic osteosarcoma and had a survival of 46% at 5 years. Older patients had less chemotherapy and fared worse. Osteosarcoma in the elderly is a curable condition and warrants intensive treatment with chemotherapy and surgical resection.

Indications for epiphyseal preservation in metaphyseal malignant bone tumors of children: relationship between image methods and histological findings

We compared several image methods in the evaluation of the possible physeal effect in 47 osteosarcomas and 18 Ewing's sarcomas in children. The minimal follow-up was 3 years (range, 3-17). In the histological study, the physis was affected in 53% of the cases. We correlated the histological findings and the findings from the different image methods. There were more false-positive than false-negative results, and in the computed tomography and magnetic resonance imaging (MRI) studies, there were no false negatives. The accuracy of MRI (predictive positive value plus predictive negative value) was the best (90.3%), and it is the technique that we prefer. According to these findings, we can safely preserve the epiphysis in cases of metaphyseal tumors showing no contact between the tumor and the growth plate in the MRI images. If the tumor shows contact with part of the physis, it is also possible to preserve the epiphysis.

External fixation in tumour pathology

An appraisal of the clinical records of patients with malignant bone tumours enabled us to identify 61 whom we have treated by external fixation. There were 38 males and 23 females with ages ranging from 4 to 58 years, the mean being 14 years. The average period of follow-up was 6 years (1-12 years). For the purpose of our analysis the patients were divided into three groups according to whether the fixator was fitted before, during or after tumour resection.

Fractures of allografts used in limb preserving operations

One hundred and thirty-seven allografts used since 1986 in limb preserving operations for malignant bone tumours were reviewed. The follow up was longer than two years. There were fourteen fractures (10.2%) in twelve patients at a mean time of 22 months from the operation. Most of them were in the metaphyseal area and were related to perforations of the allograft made for stabilisation with plates, for tendon and ligament reattachment, or any other hole in the allograft. Fractures occurred always after the allograft-host junction was united. Healing was achieved in 7 cases by internal fixation with autologous bone grafting in a mean of 5 months. In cases of multiple fractures of the allograft, the graft was exchanged. We recommend using intramedullary fixation in order to reduce the incidence of allograft fracture, and the use of internal fixation, with intramedullary whenever possible, and autologous bone grafting to achieve consolidation of the fractures.