Stem cell-like reprogramming is required for leukemia-initiating activity in B-ALL

B cell acute lymphoblastic leukemia (B-ALL) is a multistep disease characterized by the hierarchical acquisition of genetic alterations. However, the question of how a primary oncogene reprograms stem cell-like properties in committed B cells and leads to a preneoplastic population remains unclear. Here, we used the PAX5::ELN oncogenic model to demonstrate a causal link between the differentiation blockade, the self-renewal, and the emergence of preleukemic stem cells (pre-LSCs). We show that PAX5::ELN disrupts the differentiation of preleukemic cells by enforcing the IL7r/JAK-STAT pathway. This disruption is associated with the induction of rare and quiescent pre-LSCs that sustain the leukemia-initiating activity, as assessed using the H2B-GFP model. Integration of transcriptomic and chromatin accessibility data reveals that those quiescent pre-LSCs lose B cell identity and reactivate an immature molecular program, reminiscent of human B-ALL chemo-resistant cells. Finally, our transcriptional regulatory network reveals the transcription factor EGR1 as a strong candidate to control quiescence/resistance of PAX5::ELN pre-LSCs as well as of blasts from human B-ALL.

Efficacy and safety of crizotinib in ALK-positive systemic anaplastic large-cell lymphoma in children, adolescents, and adult patients: results of the French AcSé-crizotinib trial

BACKGROUND

The French phase II AcSé-crizotinib trial aimed to evaluate the safety and efficacy of crizotinib in patients with ALK, ROS1, and MET-driven malignancies, including ALK-positive anaplastic large-cell lymphoma (ALK+ ALCL).

METHODS

ALK+ ALCL patients 12 months or older with measurable disease and no standard care options available received crizotinib twice daily at 165 mg/m2 in children and adolescents and 250 mg in adults. The primary end-point was the response rate at 8 weeks.

RESULTS

Twenty-eight patients were enroled between February 2014 and March 2018. Three patients who were not treated were excluded from the analysis. The median age was 19 years. The median previous line of chemotherapy was two. In the 24 patients with an evaluable response, the response rate at 8 weeks was 67% (95% CI: 47-82%). All patients discontinued crizotinib after a median treatment duration of 3.7 months: eight for progression, two for adverse events (AEs) related to prior treatments, and 15 by choice, including six for allogeneic stem-cell transplantation. The median follow-up was 45 months. Nine patients experienced an event: eight relapses (seven after crizotinib discontinuation and one after dose reduction), and one died in complete remission. The median duration of response was 43.3 months (95% CI: 8.3-not reached). The 3-year progression-free and overall survival rates were 40% (95% CI: 23-59%) and 63% (95% CI: 43-79%). Grade 3 or 4 treatment-related AEs occurred in 32% of patients.

CONCLUSION

Crizotinib shows efficacy and an acceptable safety profile in ALK+ ALCL relapsed/refractory patients. However, a large proportion of patients experience a relapse after crizotinib discontinuation. Future studies will assess if prolonged ALK inhibitor exposure has curative potential without consolidation.

Longitudinal characterization of primary osteosarcoma and derived subcutaneous and orthotopic relapsed patient-derived xenograft models

Osteosarcoma is a rare bone cancer in adolescents and young adults with a dismal prognosis because of metastatic disease and chemoresistance. Despite multiple clinical trials, no improvement in outcome has occurred in decades. There is an urgent need to better understand resistant and metastatic disease and to generate in vivo models from relapsed tumors. We developed eight new patient-derived xenograft (PDX) subcutaneous and orthotopic/paratibial models derived from patients with recurrent osteosarcoma and compared the genetic and transcriptomic landscapes of the disease progression at diagnosis and relapse with the matching PDX. Whole exome sequencing showed that driver and copy-number alterations are conserved from diagnosis to relapse, with the emergence of somatic alterations of genes mostly involved in DNA repair, cell cycle checkpoints, and chromosome organization. All PDX patients conserve most of the genetic alterations identified at relapse. At the transcriptomic level, tumor cells maintain their ossification, chondrocytic, and trans-differentiation programs during progression and implantation in PDX models, as identified at the radiological and histological levels. A more complex phenotype, like the interaction with immune cells and osteoclasts or cancer testis antigen expression, seemed conserved and was hardly identifiable by histology. Despite NSG mouse immunodeficiency, four of the PDX models partially reconstructed the vascular and immune-microenvironment observed in patients, among which the macrophagic TREM2/TYROBP axis expression, recently linked to immunosuppression. Our multimodal analysis of osteosarcoma progression and PDX models is a valuable resource to understand resistance and metastatic spread mechanisms, as well as for the exploration of novel therapeutic strategies for advanced osteosarcoma.

Somatic genetic alterations predict haematological progression in GATA2 deficiency

Germline GATA2 mutations predispose to myeloid malignancies resulting from the progressive acquisition of additional somatic mutations. Here we describe clinical and biological features of 78 GATA2 deficient patients. Hematopoietic stem and progenitor cell phenotypic characterization revealed an exhaustion of myeloid progenitors. Somatic mutations in STAG2, ASXL1 and SETBP1 genes along with cytogenetic abnormalities (monosomy 7, trisomy 8, der(1;7)) occurred frequently in patients with GATA2 germline mutations. Patients were classified into three haematopoietic spectra based on bone marrow cytomorphology. No somatic additional mutations were detected in patients with normal bone marrow (spectrum 0), whereas clonal haematopoiesis mediated by STAG2 mutations was frequent in those with a hypocellular and/or myelodysplastic bone marrow without excess blasts (spectrum 1). Finally, SETBP1, RAS pathway and RUNX1 mutations were predominantly associated with leukemic transformation stage (spectrum 2), highlighting their implications in the transformation process. Specific somatic alterations, potentially providing distinct selective advantages to affected cells, are therefore associated with the clinical/haematological evolution of GATA2 syndrome. Our study not only suggests that somatic genetic profiling will help clinicians for their management of patients, but also clarify the mechanism of leukemogenesis in the context of germline GATA2 mutations.

[Is a preanesthetic interview by a team including nurses effective, safe, and efficient?]

OBJECTIVE

To analyze the effectiveness, safety, and performance of anesthetist-led preanesthetic interviews in which specifically trained nurses exercise defined roles under supervision.

MATERIAL AND METHODS

This descriptive study analyzed preanesthetic interviews performed by a team of anesthesiologists and nurses in surgically treated patients over a 1-year period. We assessed the impact of those interviews on the rate of procedures canceled due to errors in presurgical assessment. Study variables were the percentage of procedures canceled due to failure of presurgical assessment and the difference in the cancellation rate according to whether the interviews were undertaken by anesthesiologists or nurses, number of preanesthetic assessments made by nurses; number of consultations made by nurses to anesthesiologists, number of patients referred for a second interview with an anesthesiologist after assessment by a nurse, rate of substitution by nurses of anesthesiologists, and time dedicated daily by anesthesiologists responding to nurses' consultations. The results were analyzed using descriptive statistics.

RESULTS

A total of 7343 preoperative assessments were performed. Of those, 28.6% were undertaken by nurses. Surgery was canceled because of errors in presurgical assessment in 78 cases (1.06%), corresponding to 1.0% of the preoperative evaluations performed by anesthesiologists and 0.7% of those performed by nurses. In 317 (18.2%) nurse-led preoperative assessments the anesthesiologist was consulted, and in another 121 cases (6.9%) a second preanesthetic interview was required. The rate of substitution of anesthesiologists by nursing staff was 26.5% and the time anesthesiologists dedicated daily to consultation during nurse-led assessments was 17.7 minutes.

CONCLUSIONS

The involvement of nurses in preanesthesia assessments of surgical patients is a clinically safe and effective initiative.

Prognostic factors in laryngotracheal injury following intubation and/or tracheotomy in ICU patients

The aim of this study was to determine the incidence of laryngotracheal injuries following intubation and/or tracheotomy in intensive care unit (ICU) patients and to analyze their prognostic factors. This prospective study includes the clinical data and endoscopic exploration of 654 ICU patients who underwent oro-tracheal intubation between September 1992 and February 1999. The prognostic factors for upper airway injuries were analyzed using a multivariate statistical study. Endoscopic exploration of the upper airway 6 to 12 months after extubation revealed laryngotracheal injuries in 30 of the 280 patients examined (11%). The most important factors influencing the development of laryngotracheal lesions were the duration of the oro-tracheal intubation and the length of time in the ICU. Patients at high risk of developing injuries were those with pathological background, a non-neurological or non-surgical (medical) admission or upper-airway injuries at an early stage. The length of oro-tracheal intubation is the most important factor in the development of laryngotracheal injuries. Consequently, it is essential to establish a time limit to perform tracheotomy in ICU patients. Such timing should be adapted to each patient and pathology.

The utility of serology in diagnosing candidosis in non-neutropenic critically ill patients

This study was carried out to evaluate the utility of serological tests in the diagnosis of candidal infections in non-neutropenic critically ill patients. A prospective study was carried out in a 10-bed general intensive care unit; all patients with at least one organic sample with Candida spp. were included. A therapeutic-diagnostic algorithm was designed, and patients were treated or not, according to a classification. Blood samples were taken, and serological tests included: antigenaemia detection using two different commercial latex kits (Cand-Tec and Pastorex) and antibody detection by indirect haemagglutination (IHA) and indirect germ tube immunofluorescence (IFA). A total of 56% of antibody tests (IHA 45% and IFA 64%) and 26% of antigen tests (Cand-Tec 36% and Pastorex 17%) were positive. The sensitivity and specificity of these tests with respect to systemic candidosis were 37% and 78%, respectively, for antibodies, and 0% and 90% for antigens. There was statistical significance for mortality and low levels of antibodies; Candida glabrata was detected by IFA and Candida tropicalis by Cand-Tec. Serological tests may help to define the prognosis of these patients and to support the detection of specific Candida species.

[Traumatic rupture of the tricuspid valve. Its conservative surgical treatment]

Tricuspid insufficiency caused by blunt chest trauma is rare and usually unsuspected clinically, early after trauma. Cross-sectional Echocardiography and Cardiac Catheterization are essential to establish the diagnosis. Therapy applied varies from repair to valvular replacement. We describe an 18-year-old boy with traumatic tricuspid regurgitation treated by reconstruction of the attachments of the anterosuperior leaflet and annuloplasty with a Puig-Massana ring. Six month after surgery he is fully recovered, although persist a moderate degree of tricuspid insufficiency.

[Review of tetanus points of entry. Study of 229 cases]

A revision of tetanus points of entry in 229 tetanic patients who were cared for at the Hospital del Mar, Barcelona, between 1970 and 1983, i carried out in order to determine in which kind of patients a adequate prophylaxis is not performed. It is found that 83% of point of entry are wounds which are not medically assisted. At the same time points of entry are classified in four main groups: a first group consisting of wounds localized in head and extremities (46.8%), second group to contaminated intramuscular injections (21.8%) a third group related to surgical and obstetric procedures (15.3%) an a fourth group which includes other points of entry not included in the previous groups (16.2%). This classification permits the detection of epidemiological characteristics of each group and the observation of the possible influence of point of entry on the evolution and prognosis of tetanus highlighting that the most severe situations are due to intramuscular injections and surgical and obstetric procedures. With this study we can conclude that an adequate antitetanic prophylaxis must not be restricted to high risk patients, but should be extended to the whole population.