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Patient-derived xenografts (PDXs) can be improved by implantation of a humanized niche. Nevertheless, the overall complexity of the current protocols, as well as the use of specific biomaterials and procedures, limits the wider adoption of this approach. Here, we identify the essential minimum steps required to create the humanized scaffolds and achieve successful acute myeloid leukemia (AML) engraftment. We compared seven biomaterials, which included both published and custom-designed materials. The highest level of bone marrow niche was achieved with extracellular matrix gels and custom collagen fiber, both of which allowed for a simple non-surgical implantation. The biomaterial selection did not influence the following AML infiltration. Regarding xenotransplantation, standard intravenous administration produced the most robust engraftment, even for two out of four otherwise non-engrafting AML samples. In contrast, direct intra-scaffold xenotransplantation did not offer any advantage. In summary, we demonstrate that the combination of an injectable biomaterial for scaffold creation plus an intravenous route for AML xenotransplantation provide the most convenient and robust approach to produce AML PDX using a humanized niche., (© 2025 The Author(s). Molecular Oncology published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Background: Anti-CD19 chimeric antigen receptor T cells (CART-19) frequently induce remissions in hemato-oncological patients with recurred and/or refractory B-cell tumors. However, malignant cells sometimes escape the immunotherapeutic targeting by CD19 gene mutations, alternative splicing or lineage switch, commonly causing lack of CD19 expression on the surface of neoplastic cells. We assumed that, in addition to the known mechanisms, other means could act on CD19 to drive antigen-negative relapse., Methods: Herein, we studied the mechanism of antigen loss in an in vivo CD19-negative recurrence model of chronic lymphocytic leukemia (CLL) to CART-19, established using NOD- scid IL2Rg null mice and HG3 cell line. We validated our findings in vitro in immortalized B-cell lines and primary CLL cells., Results: In our in vivo CLL recurrence model, up to 70% of CART-19-treated mice eventually recurred with CD19-negative disease weeks after initial positive response. We found that the lack of CD19 expression was caused by promoter DNA hypermethylation. Importantly, the expression loss was partially reversible by treatment with a demethylating agent. Moreover, this escape mechanism was common for 3 B-cell immortalized lines as well as primary CLL cells, as assessed by in vitro coculture experiments., Conclusions: Epigenetically driven antigen escape could represent a novel, yet at least partially reversible, means of CD19 loss to CART-19 in B-cell tumors., Competing Interests: Competing interests: None., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

There is an emerging body of evidence that patients with chronic myeloid leukaemia (CML) may carry not only breakpoint cluster region-Abelson murine leukaemia viral oncogene homologue 1 (BCR-ABL1) kinase domain mutations (BCR-ABL1 KD mutations), but also mutations in other genes. Their occurrence is highest during progression or at failure, but their impact at diagnosis is unclear. In the present study, we prospectively screened for mutations in 18 myeloid neoplasm-associated genes and BCR-ABL1 KD in the following populations: bulk leucocytes, CD34 + CD38 + progenitors and CD34 + CD38 - stem cells, at diagnosis and early follow-up. In our cohort of chronic phase CML patients, nine of 49 patients harboured somatic mutations in the following genes: six ASXL1 mutations, one SETBP1, one TP53, one JAK2, but no BCR-ABL1 KD mutations. In seven of the nine patients, mutations were detected in multiple hierarchical populations including bulk leucocytes at diagnosis. The mutation dynamics reflected the BCR-ABL1 transcript decline induced by treatment in eight of the nine cases, suggesting that mutations were acquired in the Philadelphia chromosome (Ph)-positive clone. In one patient, the JAK2 V617F mutation correlated with a concomitant Ph-negative myeloproliferative neoplasm and persisted despite a 5-log reduction of the BCR-ABL1 transcript. Only two of the nine patients with mutations failed first-line therapy. No correlation was found between the mutation status and survival or response outcomes., (© 2021 British Society for Haematology and John Wiley & Sons Ltd.)

Genetic mutations in acute myeloid leukaemia (AML) are assumed to occur in a sequential order; however, the predominant hierarchical roles of specific mutated genes have not been fully described. In this study, we aimed to determine the clonal involvement of the most frequent AML-associated mutations. Using a targeted sequencing panel for 18 genes, we traced changes and relative clonal contribution of mutations in 52 patients. We analysed 35 pairs of diagnosis and relapse samples, 27 pairs of primary samples and corresponding patient-derived xenografts, and 34 pairs of total leukocytes and corresponding isolated primitive cells or blast populations. In both relapse and xenografts, we observed conservation of main leukaemic clones and variability was limited to subclones with late-acquired mutations. AML evolution thus mainly involved modification of subclones while the clonal background remained unchanged. NPM1 mutations were identified as the most probable leukaemia-transformation lesion, remaining conserved in contrast to high variation of accompanying subclonal FLT3 and NRAS mutations. DNMT3A mutations represented the most stable mutations forming a preleukaemic background in most samples. Mutations in genes IDH1/2, TET2, RUNX1, ASXL1 and U2AF1 were detected both as preleukaemic and as subclonal lesions, suggesting a non-specific order of acquisition., (© 2019 British Society for Haematology and John Wiley & Sons Ltd.)

The occurrence of mutations in the BCR-ABL1 kinase domain (KD) can lead to treatment resistance in chronic myeloid leukaemia patients. Nowadays, next-generation sequencing (NGS) is an alternative method for the detection of kinase domain mutations, compared to routinely used Sanger sequencing, providing a higher sensitivity of mutation detection. However, in the protocols established so far multiple rounds of amplification limit reliable mutation detection to approximately 5% variant allele frequency. Here, we present a simplified, one-round amplification NGS protocol for the Illumina platform, which offers a robust early detection of BCR-ABL1 KD mutations with a reliable detection limit of 3% variant allele frequency., (© 2020 British Society for Haematology and John Wiley & Sons Ltd.)

In this multi-centre study, we analysed the prognostic impact of mutations in 19 genes associated with myeloid malignancies in 258 newly diagnosed acute myeloid leukaemia patients (aged 19-70 years) undergoing intensive therapy. We identified five patient groups with different prognostic risks and different benefits from allogeneic hematopoietic stem cell transplantation (alloHSCT) within the intermediate cytogenetic risk group patients (n = 184). The most adverse prognosis was observed in patients with DNMT3A and FLT3-ITD co-mutation, whose survival could be significantly improved with alloHSCT. In contrast, the most favourable prognosis without any further benefit from alloHSCT was identified in patients with mutations in NPM1 or CEBPA, after exclusion of the unfavourable prognostic groups defined by mutations in DNMT3A, RUNX1 or genes from chromatin/spliceosome group. An additional analysis of 113 diagnosis-remission paired samples revealed that persistence of non-DNMT3A mutations (above 2% VAF) represented a further negative prognostic factor. The proposed model offers a possible molecular stratification and treatment guidance for intermediate cytogenetic risk group patients., (© 2019 British Society for Haematology and John Wiley & Sons Ltd.)

Purpose: This study aimed at analyzing the association of gene mutations and other acute myeloid leukemia (AML) characteristics with engraftment outcomes in immunodeficient mice and to select the engraftment outcomes that best reflect patient survival., Methods: Mutations in 19 genes as well as leukemia- and patient-related characteristics were analyzed for a group of 47 de novo AML samples with respect to three engraftment outcomes: engraftment ability, engraftment intensity (percentage of hCD45 + cells) and engraftment latency. Leukemia-related characteristics were additionally analyzed in an extended group of 68 samples that included the 47 de novo samples, and additional 21 samples from refractory and relapsed cases. Engraftment outcomes were compared with overall and event-free survival of the patients., Results: For the 47 de novo samples, no single mutation influenced engraftment, whereas the NPM1 mut /DNMT3A mut co-mutation was associated with higher engraftment ability. NPM1 mut /FLT3-ITD neg had lower engraftment intensity. Among leukemia-related characteristics, a complex karyotype was associated with higher engraftment intensity. Among patient-related characteristics, higher cytogenetic risk was associated with higher engraftment intensity, and failure to achieve clinical remission was associated with shorter engraftment latency. In the extended group of 68 samples, white blood count was associated with higher engraftment ability, and the presence of a complex karyotype was associated with higher engraftment intensity. Association with patient overall survival was seen only for engraftment intensity., Conclusions: The engraftment of AML was influenced by mutation-interactions and other AML characteristics, rather than by single mutated genes, and engraftment intensity best reflected clinical penetrance of AML.

Little is known about the function and phenotype of leukemic stem cells (LSCs) in chronic myeloid leukemia (CML) or about specific markers that discriminate LSCs from normal hematopoietic stem cells (HSCs). CD26 has recently been described as a specific marker of CML LSCs. In the current study, we investigated this marker in a cohort of 31 unselected CML patients. BCR/ABL1 positivity was analyzed in highly enriched stem cell fractions using fluorescence in situ hybridization (FISH) and reverse transcription PCR (RT-PCR). The proportion of CD26+ LSCs and CD26- HSCs varied considerably among the patients analyzed, and the percentage of CD26+ cells correlated with leukocyte count. The CD26 expression robustly discriminated LSCs from HSCs. This required a strict gating of the stem cell compartment. Thus, in patients with very low LSC or HSC numbers, only the highly sensitive RT-PCR method discriminated between clonal and non-clonal cells, while a robust FISH analysis required larger numbers of cells in both compartments. Finally, our data show that the numbers of CD26+ CML LSCs correlate with responses to treatment with BCR-ABL1 inhibitors., Competing Interests: P.V. has received research funding and honoraria from BMS, Novartis and Ariad. The other authors have no conflicts of interest to disclose in this study.

The DNA methyl-transferase 3A gene (DNMT3A) is the third most frequently mutated gene in cytogenetically normal acute myeloid leukemia (CN-AML) patients (20-30 %), who belong to a group of patients with intermediate risk. About 60 % of mutations in this gene have been identified in the arginine codon R882. To date, there is no consensus on whether these mutations can be used as biomarkers for monitoring of minimal residual disease and management of preemptive AML therapy. We studied the occurrence of mutations in the DNMT3A gene in our cohort of patients and their persistence during AML treatment. Using next-generation sequencing, we identified four mutations in 11/25 of our analyzed patients--frequent R882C and R882H mutations, rare Y735S mutation, and a novel L347P mutation. Mutation R882C was detected in 5/11, R882H in 4/11 patients, and Y735S and L347P in one patient each. In 4/7 patients initially carrying mutations in the R882 codon, we found the persistence of mutations also during complete remission with, however, no correlation to AML kinetics. Our findings suggest that mutations in the DNMT3A gene can only be used as a biomarker for those AML patients in whom DNMT3A mutation is lost after therapy.

The rising demands on discriminatory and prediction abilities of dissolution methods and the increasing complexity of new drug products are the main driving forces of the progress in this field. The research moves forward as imperfections and shortcomings of classical methods are being described, and where the capabilities of the contemporary methods are insufficient, new methods are being developed. The review discusses these advances with respect to the issues that currently draw the most attention, i.e. correct simulation of hydrodynamics and stress forces, maintenance of sink conditions, study of precipitation, use of biorelevant media and the employment of more physiologically relevant methods in general.

Development of new pharmaceutical compounds and dosage forms often requires in vitro dissolution testing with the closest similarity to the human gastrointestinal (GI) tract. To create such conditions, one needs a suitable dissolution apparatus and the appropriate data on the human GI physiology. This review discusses technological approaches applicable in biorelevant dissolutions as well as the physiology of stomach and small intestine in both fasted and fed state, that is, volumes of contents, transit times for water/food and various solid oral dosage forms, pH, osmolality, surface tension, buffer capacity, and concentrations of bile salts, phospholipids, enzymes, and Ca(2+) ions. The information is aimed to provide clear suggestions on how these conditions should be set in a dynamic biorelevant dissolution test., (Copyright © 2013 Wiley Periodicals, Inc.)

The studied series consisted of 14 patients with ventricular septal defect and pulmonary hypertension aged from 3 months to 15 years. Three examination methods were compared: (1) Invasive hemodynamic examination; (2) Pulmoangiographic examination by means of wedge peripheral pulmoangiography; (3) Histological examination of bioptic samples. Direct correlation was found to exist between mean PA pressure, PAR/m2, TPR/SR and pulmoangiographic records, in which the following parameters were evaluated: (a) length of the narrowing of the peripheral branch of the PA, (b) background opacity, (c) circulation time. The histological findings obtained in the bioptic samples corresponded practically in all cases with the hemodynamic and PAG findings. Only in two patients did the histological picture display a less severe degree of affection than found by PAG and hemodynamic examination. The obtained results suggest that in light of surgical indications, PAG can be considered a suitable and valuable supplementary method in assessing borderline findings of pulmonary hypertension in children with congenital heart defects and left-to-right shunt.

In 13 children supravalvular aortic stenosis was diagnosed by two-dimensional echocardiography on the basis of a diminished inner diameter of the aorta in the supravalvular region "d2" compared with the inner diameter of the aortic annulus "d1". The differences in the values of "d2" and "d1" were only on the border of statistical significance. The difference in the d2/d1 ratio between the group of patients and healthy controls was statistically significant (p less than 0.001). Two-dimensional echocardiography is a very sensitive method for diagnosing supravalvular aortic stenosis. This sensitivity has been confirmed also by detecting the diminished inner diameter of the aorta in the supravalvular region in children with Williams-Beuren syndrome without clinical signs of a heart defect.