Die Rolle von SRSF2 und TP53 in der Progression chronisch myeloproliferativer Erkrankungen - Eine Untersuchung an seriellen Knochenmarkbiopsien

In den vergangenen Jahren wurden bei myeloproliferativen Erkrankungen zahlreiche Mutationen beschrieben, über deren genaue molekulare Mechanismen oder die zeitliche Abfolge, im Sinne einer klonalen Evolution, deren prognostische Wertigkeit sowie deren Korrelation mit Knochenmarkmorphologie und Klinik war jedoch wenig bekannt. In der vorliegenden Arbeit wurden Verläufe von myeloproliferativen Erkrankungen und MDS/MPN an sequentiellen Knochenmarkbiopsien untersucht. Es wurde sowohl der morphologische als auch der klinische Verlauf zur Einordnung in Gruppen betrachtet und die Verläufe mit einer Untersuchung von molekularen Mechanismen der Progression, dem zeitlichen Verlauf der Mutationen und möglicher additiver Effekte dieser Mutationen korreliert. Ein besonderer Fokus lag auf der Bedeutung der Mutationen im SRSF2- und im TP53-Gen. Die Untersuchungen erfolgten an einem Studienkollektiv von insgesamt 133 Fällen bzw. 75 Patienten, von denen 30 Patienten (37,3%) progredient waren, 45 Patienten (62,7%) eine stabile myeloproliferative Erkrankung (Kontrollgruppe) hatten. Es zeigte sich, dass die SRSF2-Mutation signifikant häufiger in der Gruppe der progredienten myeloproliferativen Erkrankungen vorkam, insbesondere bei Progression in Richtung eines MDS. Als frühe somatische Mutation eignet sich die Mutation möglicherweise schon bei Erstdiagnose zur Risikostratifizierung. Ebenso stellt die SRSF2-Mutation bei MDS/MPN-UC eine sehr häufige Mutation dar, kann somit als ein mögliches diagnostisches Werkzeug dienen. Das Auftreten einer TP53 Überexpression verursacht bei einem Teil der Patienten eine Transformation der MPN in Richtung einer akuten myeloischen Leukämie, es zeigte die in der Literatur beschriebene Tendenz, dass TP53-Mutationen erst zum Zeitpunkt einer leukämischen Transformation auftreten. Im untersuchten Kollektiv kamen SRSF2- und starke TP53 Überexpression als Hinweis auf Mutation nicht gemeinsam vor, JAK2- und SRSF2-Mutation waren ebenfalls seltener koinzident. Wie durch Vorarbeiten bei der CMML gezeigt, lässt sich mittels RFLP der SRSF2-Mutationsstatus zuverlässig und schnell aus dem Knochenmark-trepanat identifizieren, in der vorliegenden Arbeit konnte dies bei den verschiedenen MPN-Entitäten, sekundären MDS, MDS/MPN und sekundären akuten myeloischen Leukämien gezeigt werden. Die immunhistochemische Methode zur Darstellung der TP53-Überexpression von Saft et al. eignet sich gut um Fälle mit erhöhtem Risiko der Progression am Knochenmarktrepanat festzustellen

Haploidentical hematopoietic stem cell transplantation as individual treatment option in pediatric patients with very high-risk sarcomas

Background Prognosis of children with primary disseminated or metastatic relapsed sarcomas remains dismal despite intensification of conventional therapies including high-dose chemotherapy. Since haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is effective in the treatment of hematological malignancies by mediating a graft versus leukemia effect, we evaluated this approach in pediatric sarcomas as well. Methods Patients with bone Ewing sarcoma or soft tissue sarcoma who received haplo-HSCT as part of clinical trials using CD3+ or TCRα/β+ and CD19+ depletion respectively were evaluated regarding feasibility of treatment and survival. Results We identified 15 patients with primary disseminated disease and 14 with metastatic relapse who were transplanted from a haploidentical donor to improve prognosis. Three-year event-free survival (EFS) was 18,1% and predominantly determined by disease relapse. Survival depended on response to pre-transplant therapy (3y-EFS of patients in complete or very good partial response: 36,4%). However, no patient with metastatic relapse could be rescued. Conclusion Haplo-HSCT for consolidation after conventional therapy seems to be of interest for some, but not for the majority of patients with high-risk pediatric sarcomas. Evaluation of its future use as basis for subsequent humoral or cellular immunotherapies is necessary

Combined Metabolic and Functional Tumor Volumes on [¹⁸F]FDG-PET/MRI in Neuroblastoma Using Voxel-Wise Analysis

Purpose: The purpose of our study was to evaluate the association between the [18F]FDG standard uptake value (SUV) and the apparent diffusion coefficient (ADC) in neuroblastoma (NB) by voxel-wise analysis. Methods: From our prospective observational PET/MRI study, a subcohort of patients diagnosed with NB with both baseline imaging and post-chemotherapy imaging was further investigated. After registration and tumor segmentation, metabolic and functional tumor volumes were calculated from the ADC and SUV values using dedicated software allowing for voxel-wise analysis. Under the mean of thresholds, each voxel was assigned to one of three virtual tissue groups: highly vital (v) (low ADC and high SUV), possibly low vital (lv) (high ADC and low SUV), and equivocal (e) with high ADC and high SUV or low ADC and low SUV. Moreover, three clusters were generated from the total tumor volumes using the method of multiple Gaussian distributions. The Pearson’s correlation coefficient between the ADC and the SUV was calculated for each group. Results: Out of 43 PET/MRIs in 21 patients with NB, 16 MRIs in 8 patients met the inclusion criteria (PET/MRIs before and after chemotherapy). The proportion of tumor volumes were 26%, 36%, and 38% (v, lv, e) at baseline, 0.03%, 66%, and 34% after treatment in patients with response, and 42%, 25%, and 33% with progressive disease, respectively. In all clusters, the ADC and the SUV correlated negatively. In the cluster that corresponded to highly vital tissue, the ADC and the SUV showed a moderate negative correlation before treatment (R = −0.18; p p n = 2) under therapy had a relevant part in this cluster post-treatment. Conclusion: Our results indicate that voxel-wise analysis of the ADC and the SUV is feasible and can quantify the different quality of tissue in neuroblastic tumors. Monitoring ADCs as well as SUV levels can quantify tumor dynamics during therapy

Antiemetic Prophylaxis with Fosaprepitant and 5-HT3-Receptor Antagonists in Pediatric Patients Undergoing Autologous Hematopoietic Stem Cell Transplantation

Background: High-dose myeloablative conditioning prior to autologous hematopoietic stem cell transplantation (autoHSCT) in pediatric patients is usually highly emetogenic. The antiemetic neurokinin-1 receptor antagonist fosaprepitant was safe and effective in children receiving highly emetogenic chemotherapy. Data on fosaprepitant during autoHSCT in children are currently not available. Methods: A total of 35 consecutive pediatric patients, who received an antiemetic prophylaxis with fosaprepitant (4 mg/kg;single dose, max. 1 x 150 mg/kg BW) and ondansetron (24-hours continuous infusion;8-32 mg/24h) or granisetron (2 x 40 mu g/kg.d(-1)) during highly emetogenic conditioning chemotherapy before autoHSCT were retrospectively analyzed, and their results were compared with a control group comprising 35 consecutive pediatric patients, who received granisetron or ondansetron only. The antiemetic efficacy and the safety of the two prophylaxis regimens were compared with respect to three time periods after the first chemotherapy administration (0-24h, >24-120h, >120-240h). Results: Clinical adverse events and clinically relevant increases/decreases of laboratory markers were similarly low and did not significantly differ between the two study groups (p>0.05). The registered number of vomiting events was significantly higher in the control group in the time periods of 0-24h (64 vs 22 events;p24-120h (135 vs 78 events;p120-240h (268 vs 105 events;p24-120h (100% vs 74.3%) but not the other analyzed time periods (p>0.05). Conclusion: The fosaprepitant-based antiemetic prophylaxis was safe, well tolerated and significantly reduced vomiting in children undergoing highly emetogenic chemotherapy prior to autoHSCT. Prospective randomized trials are necessary to confirm these results

Molecular Progression of Myeloproliferative and Myelodysplastic/Myeloproliferative Neoplasms: A Study on Sequential Bone Marrow Biopsies

Myeloproliferative neoplasms (MPN) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN) both harbor the potential to undergo myelodysplastic progression or acceleration and can transform into blast-phase MPN or MDS/MPN, a form of secondary acute myeloid leukemia (AML). Although the initiating transforming events are yet to be determined, current concepts suggest a stepwise acquisition of (additional) somatic mutations—apart from the initial driver mutations—that trigger disease evolution. In this study we molecularly analyzed paired bone marrow samples of MPN and MDS/MPN patients with known progression and compared them to a control cohort of patients with stable disease course. Cases with progression displayed from the very beginning a higher number of mutations compared to stable ones, of which mutations in five (ASXL1, DNMT3A, NRAS, SRSF2 and TP53) strongly correlated with progression and/or transformation, even if only one of these genes was mutated, and this particularly applied to MPN. TET2 mutations were found to have a higher allelic frequency than the putative driver mutation in three progressing cases (“TET2-first”), whereas two stable cases displayed a TET2-positive subclone (“TET2-second”), supporting the hypothesis that not only the sum of mutations but also their order of appearance matters in the course of disease. Our data emphasize the importance of genetic testing in MPN and MDS/MPN patients in terms of risk stratification and identification of imminent disease progression