Human gene-engineered calreticulin mutant stem cells recapitulate MPN hallmarks and identify targetable vulnerabilities.

Calreticulin (CALR) mutations present the main oncogenic drivers in JAK2 wildtype (WT) myeloproliferative neoplasms (MPN), including essential thrombocythemia and myelofibrosis, where mutant (MUT) CALR is increasingly recognized as a suitable mutation-specific drug target. However, our current understanding of its mechanism-of-action is derived from mouse models or immortalized cell lines, where cross-species differences, ectopic over-expression and lack of disease penetrance are hampering translational research. Here, we describe the first human gene-engineered model of CALR MUT MPN using a CRISPR/Cas9 and adeno-associated viral vector-mediated knock-in strategy in primary human hematopoietic stem and progenitor cells (HSPCs) to establish a reproducible and trackable phenotype in vitro and in xenografted mice. Our humanized model recapitulates many disease hallmarks: thrombopoietin-independent megakaryopoiesis, myeloid-lineage skewing, splenomegaly, bone marrow fibrosis, and expansion of megakaryocyte-primed CD41+ progenitors. Strikingly, introduction of CALR mutations enforced early reprogramming of human HSPCs and the induction of an endoplasmic reticulum stress response. The observed compensatory upregulation of chaperones revealed novel mutation-specific vulnerabilities with preferential sensitivity of CALR mutant cells to inhibition of the BiP chaperone and the proteasome. Overall, our humanized model improves purely murine models and provides a readily usable basis for testing of novel therapeutic strategies in a human setting.

Distinct Chemokine Receptor Expression Profiles in De Novo DLBCL, Transformed Follicular Lymphoma, Richter's Trans-Formed DLBCL and Germinal Center B-Cells.

Chemokine receptors and their ligands have been identified as playing an important role in the development of diffuse large B-cell lymphoma (DLBCL), follicular lymphoma, and Richter syndrome (RS). Our aim was to investigate the different expression profiles in de novo DLBCL, transformed follicular lymphoma (tFL), and RS. Here, we profiled the mRNA expression levels of 18 chemokine receptors (CCR1-CCR9, CXCR1-CXCR7, CX3CR1 and XCR1) using RQ-PCR, as well as immunohistochemistry of seven chemokine receptors (CCR1, CCR4-CCR8 and CXCR2) in RS, de novo DLBCL, and tFL biopsy-derived tissues. Tonsil-derived germinal center B-cells (GC-B) served as non-neoplastic controls. The chemokine receptor expression profiles of de novo DLBCL and tFL substantially differed from those of GC-B, with at least 5-fold higher expression of 15 out of the 18 investigated chemokine receptors (CCR1-CCR9, CXCR1, CXCR2, CXCR6, CXCR7, CX3CR1 and XCR1) in these lymphoma subtypes. Interestingly, the de novo DLBCL and tFL exhibited at least 22-fold higher expression of CCR1, CCR5, CCR8, and CXCR6 compared with RS, whereas no significant difference in chemokine receptor expression profile was detected when comparing de novo DLBCL with tFL. Furthermore, in de novo DLBCL and tFLs, a high expression of CCR7 was associated with a poor overall survival in our study cohort, as well as in an independent patient cohort. Our data indicate that the chemokine receptor expression profile of RS differs substantially from that of de novo DLBCL and tFL. Thus, these multiple dysregulated chemokine receptors could represent novel clinical markers as diagnostic and prognostic tools. Moreover, this study highlights the relevance of chemokine signaling crosstalk in the tumor microenvironment of aggressive lymphomas.

Ultrasound in osteoarthritis of the hand: a comparison to computed tomography and histology.

OBJECTIVE: To compare structural findings between US, micro-CT (µCT) and histology in people with OA of the hands. METHODS: We analysed DIP and PIP joints of 31 fingers from 15 dissecting-room cadavers with OA of the hands. The occurrence of bone erosions and osteophytes were recorded by US, µCT and histology at 16 regions for each joint and compared for each method. RESULTS: In total, US (n = 558, 56.2% of 992 examined regions) and µCT (n = 493, 49.7%) detected a higher frequency of osteophytes at PIP and DIP joints than histology (n = 161, 23.4% of 689 histological examined regions; P = 0.01). We found a comparable number of erosions with each method [US, n = 52 (5.2%); µCT, n = 43 (4.3%); histology, n = 35 (5.2%)]. Both imaging techniques correlated moderately with each other regarding the detection of osteophytes (r = 0.54, P = 0.002) and erosions (r = 0.43, P = 0.017). Neither US nor µCT correlated with histology regarding erosions or osteophytes. With histology as the reference, US had a sensitivity of 80% and a specificity of 32% to detect osteophytes, whereas µCT had a sensitivity of 73% and a specificity of 27%. For erosions, sensitivities (US 10% and µCT 6%, respectively) were much lower. Microscopically, erosions contained fibrous myxoid tissue extending from subcortical cavities through the breach of cortical bone. CONCLUSIONS: The ability of US to identify osteophytes was comparable to that of µCT, yielding a good sensitivity when histology was used as the gold standard. The sensitivity of US and µCT to detecting erosions was low compared with histology.

Advanced isolated light chain amyloid cardiomyopathy with negative immunofixation and normal free light chain ratio.

Amyloid light chain (AL) cardiomyopathy is the most malignant specific cardiomyopathy. According to international recommendations, it should be ruled out non-invasively using the serum free light chain (FLC) ratio and immunofixation electrophoresis in both serum and urine. Here, we report on a 69-year-old female patient with new-onset heart failure with mid-range ejection fraction. Cardiac imaging was highly suggestive of cardiac amyloidosis. Amyloid scintigraphy showed faint myocardial tracer uptake according to Perugini Score 1, but immunofixation was negative and the FLC ratio was normal, despite a slight increase in lambda FLCs. Endomyocardial biopsy revealed advanced myocardial lambda immunoglobulin light chain deposition. Clinically relevant extracardiac amyloid organ infiltration could not be detected. Conclusively, non-invasive testing can in rare cases fail to exclude isolated AL amyloid cardiomyopathy. We suggest that even slight increases in serum lambda or kappa FLCs should be considered abnormal in suspected cardiac amyloidosis if non-invasive testing delivers discrepant results.

Vinorelbine as substitute for vincristine in patients with diffuse large B cell lymphoma and vincristine-induced neuropathy.

BACKGROUND: A combination of rituximab with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) is the standard first-line therapy for diffuse large B cell lymphoma (DLBCL), the most common aggressive lymphoma in adults. One of the major adverse effects of this regimen is vincristine-induced polyneuropathy which leads to discontinuation of vincristine in up to 30% of DLBCL-patients. Dose reduction of vincristine might worsen treatment outcomes of DLBCL but identification of treatment alternatives for patients exhibiting peripheral neuropathy during R-CHOP is an unmet need in hematology. METHODS: In this retrospective cohort study, comprising 987 patients with de novo DLBCL, we delineated the role of vinorelbine as a substitute for vincristine in R-CHOP by measuring improvements in neuropathy and outcome variables. RESULTS: Five-year overall survival (OS) and progression-free survival (PFS) were 72.6% and 63.1% in patients who received regular doses of vincristine, as compared to 60.6% and 51.7% in patients who received reduced doses of vincristine (p = 0.022 and p = 0.003, respectively). Of 199 patients who switched to vinorelbine, the majority experienced an improvement of neuropathy Furthermore, vinorelbine-switched patients showed favorable oncologic outcomes. CONCLUSION: Replacement of vincristine by vinorelbine due to neuropathy is effective and safe, and results in a significant improvement in neuropathy as compared to treatment with R-CHOP.

Austrian recommendations for the management of essential thrombocythemia.

According to the World Health Organization (WHO) classification, essential (primary) thrombocythemia (ET) is one of several Bcr-Abl negative chronic myeloproliferative neoplasms (MPN). The classical term MPN covers the subcategories of MPN: ET, polycythemia vera (PV), primary myelofibrosis (PMF), and prefibrotic PMF (pPMF). ET is marked by clonal proliferation of hematopoietic stem cells, leading to a chronic overproduction of platelets. At the molecular level a JAK2 (Janus Kinase 2), calreticulin, or MPL mutation is found in the majority of patients. Typical ongoing complications of the disease include thrombosis and hemorrhage. Primary and secondary prevention of these complications can be achieved with platelet function inhibitors and various cytoreductive drugs including anagrelide, hydroxyurea and interferon. After a long follow up, in a minority of ET patients the disease transforms into post-ET myelofibrosis or secondary leukemia. Overall, life expectancy with ET is only slightly decreased.

Progression, transformation, and unusual manifestations of myelodysplastic syndromes and myelodysplastic-myeloproliferative neoplasms: lessons learned from the XIV European Bone Marrow Working Group Course 2019.

Disease progression in myelodysplastic syndromes (MDS) and myelodysplastic-myeloproliferative neoplasms (MDS/MPN) is a major source of mortality. The European Bone Marrow Working Group organized a dedicated workshop to address MDS and MDS/MPN progression, and myeloid neoplasms with histiocytic and lymphoblastic outgrowths in 2019 in Frankfurt, Germany. In this report, we summarize clinical, histopathological, and molecular features of 28 cases. Most cases illustrate that prognostic mutational profiles change during follow-up due to accumulation of high-risk mutations in the trunk clone, and that results from repeated molecular testing can often explain the clinical progression, suggesting that regular genetic testing may predict transformation by early detection of aggressive clones. Importantly, identical mutations can be linked to different clinical behaviors or risks of fibrotic progression and/or transformation in a context-dependent manner, i.e., MDS or MDS/MPN. Moreover, the order of mutational acquisition and the involved cell lineages matter. Several cases exemplify that histiocytic outgrowths in myeloid neoplasms are usually accompanied by a more aggressive clinical course and may be considered harbinger of disease progression. Exceptionally, lymphoblastic transformations can be seen. As best estimable, the histiocytic and lymphoblastic compounds in all occasions were clonally related to the myeloid compound and-where studied-displayed genomic alterations of, e.g., transcription factor genes or genes involved in MAPK signaling that might be mechanistically linked to the respective type of non-myeloid outgrowth.

Bone marrow aspirations in Ewing sarcomas: Are they still necessary? A single-center retrospective analysis and review of the literature.

BACKGROUND AND OBJECTIVES: Currently, one of the most useful prognostic indicators in Ewing sarcomas (ES) is the presence of metastatic disease at diagnosis. According to various clinical guidelines, the assessment of bone marrow (BM) metastases, using light microscopy examination of bone marrow aspirates and biopsies (BMAB) is mandatory. However, the prognostic value of BM positivity is discussed controversially. Therefore, the primary aim of this study was to retrospectively review BM samples from patients with ES. MATERIALS AND METHODS: This retrospective single centre study included 31 patients that were newly diagnosed with ES between 2000 and 2014. Twenty-seven patients had skeletal ES and in 4 patients the tumour was localized in the soft tissue only. Metastases at diagnosis were present in 5 out of 31 patients. BM samples were morphologically and immunohistochemically searched and screened for the presence or absence of BM metastases. Furthermore, in 15 of the 31 patients BM samples were still available and were reanalysed, using nested-polymerase chain reaction. RESULTS: All BM samples of our 31 ES patients, including the 5 metastatic patients, were, morphologically and immunohistochemically tested negative for tumour cell appearance. The nested-PCR results were also negative in all of our 15 retested patients, including two patients with metastatic disease. CONCLUSIONS: Based on our results and on the contradictory results reported in the literature we recommend a re-evaluation of the necessity and the prognostic value of BMAB in the initial staging process of newly diagnosed ES patients.

Immunohistochemistry for c-myc and bcl-2 overexpression improves risk stratification in primary central nervous system lymphoma.

Overexpression of bcl-2 and c-myc are defining features of double-expressor-lymphoma (DEL) but may also occur separately in patients with primary central nervous system lymphoma (PCNSL). Despite all progress in optimizing treatment regimen, there is lack of sufficient risk stratification models. Here, we first describe the relationship between DEL biology, the National Comprehensive Cancer Network International Prognostic Index (NCCN-IPI), treatment response, disease progression, and mortality in PCNSL. In this study, we determined c-myc and bcl-2 status immunohistochemically in samples of 48 patients with newly diagnosed PCNSL and followed these patients for a median interval of 6.2 years. Twelve, 18, and 17 patients harbored none, one, or both DEL features. Corresponding overall response rates after first-line therapy were strongly associated with DEL biology (100%, 42%, and 44% in patients with 0, 1, or 2 DEL features). Patients with one or both DEL features had a 5-fold and 13-fold higher 5-year risk of progression and/or death than patients without DEL features. These associations prevailed after adjusting for the NCCN-IPI. DEL improved the discriminatory capability of the NCCN-IPI (P = .0001). Furthermore, we could show that addition of DEL biology to the NCCN-IPI significantly improved the score's discriminatory potential both toward progression-free survival (increase in Harell's c = 0.15, P = .005) and overall survival (increase in Harell's c = 0.11, P = .029). In conclusion, DEL biology is a strong and simple-to-use predictor of adverse outcome in PCNSL. Addition of DEL to the NCCN-IPI improves its prognostic potential. Disease progression from PCNSL harboring both DEL features is invariably fatal. This defines a novel PCNSL patient subset with a great unmet need for improved therapy.

Management of children and adolescents with gray zone lymphoma: A case series.

BACKGROUND: Data on management of gray zone lymphoma (GZL) in children and adolescents are scarce. PROCEDURE: This retrospective study assessed clinical characteristics and outcome in six Austrian patients with GZL less than 18 years of age (male-to-female ratio: 1:1; median age: 15.8 years). RESULTS: Two patients each had a classical Hodgkin lymphoma (cHL)-like and composite GZL subtype, and one patient each had a large B-cell non-Hodgkin lymphoma (LBCL)-like and sequential GZL subtype. All had advanced disease with mediastinal and extranodal involvement. Five patients received an LBCL- and one patient a cHL-directed polychemotherapy ± radiotherapy. Out of the former patients, three survived, including two who relapsed and underwent high-dose chemotherapy with autologous stem cell rescue. The latter patient survived. CONCLUSIONS: GZL remains a diagnostic and therapeutic challenge, necessitating the development of novel treatment concepts performed in a prospective setting.

Loss of RAF kinase inhibitor protein is involved in myelomonocytic differentiation and aggravates RAS-driven myeloid leukemogenesis.

RAS-signaling mutations induce the myelomonocytic differentiation and proliferation of hematopoietic stem and progenitor cells. Moreover, they are important players in the development of myeloid neoplasias. RAF kinase inhibitor protein (RKIP) is a negative regulator of RAS-signaling. As RKIP loss has recently been described in RAS-mutated myelomonocytic acute myeloid leukemia, we now aimed to analyze its role in myelomonocytic differentiation and RAS-driven leukemogenesis. Therefore, we initially analyzed RKIP expression during human and murine hematopoietic differentiation and observed that it is high in hematopoietic stem and progenitor cells and lymphoid cells but decreases in cells belonging to the myeloid lineage. By employing short hairpin RNA knockdown experiments in CD34+ umbilical cord blood cells and the undifferentiated acute myeloid leukemia cell line HL-60, we show that RKIP loss is indeed functionally involved in myelomonocytic lineage commitment and drives the myelomonocytic differentiation of hematopoietic stem and progenitor cells. These results could be confirmed in vivo, where Rkip deletion induced a myelomonocytic differentiation bias in mice by amplifying the effects of granulocyte macrophage-colony-stimulating factor. We further show that RKIP is of relevance for RAS-driven myelomonocytic leukemogenesis by demonstrating that Rkip deletion aggravates the development of a myeloproliferative disease in NrasG12D -mutated mice. Mechanistically, we demonstrate that RKIP loss increases the activity of the RAS-MAPK/ERK signaling module. Finally, we prove the clinical relevance of these findings by showing that RKIP loss is a frequent event in chronic myelomonocytic leukemia, and that it co-occurs with RAS-signaling mutations. Taken together, these data establish RKIP as novel player in RAS-driven myeloid leukemogenesis.

Choroidal Infiltration as First Clinical Manifestation of T-cell Large Granular Lymphocyte (T-LGL) Leukemia.

Purpose: To report of a 55-year-old woman suffering from choroidal infiltrates as a first clinical manifestation of T-LGL leukemia. Methods: Retrospective case report. Results: A healthy woman presented with photophobia in both eyes since 1 month. She showed a panuveitis with anterior chamber as well as vitreous cells, creamy-white choroidal lesions in both eyes and a cystoid macular edema in the left eye. Lab testing showed only a moderate lymphocytosis, all other tests, including a pars plana vitrectomy and an anterior chamber tap, were negative. Due to the persistent lymphocytosis, she was referred to the oncologist. A biopsy of the bone marrow revealed T-LGL leukemia. A subsequent biopsy of the choroid showed an infiltration of T-LGL and therefore systemic therapy with cyclophosphamide was started. Conclusions: This is a very rare case describing an involvement of the choroid in T-LGL leukemia.

The CXCR4-CXCL12-Axis Is of Prognostic Relevance in DLBCL and Its Antagonists Exert Pro-Apoptotic Effects In Vitro.

In tumor cells of more than 20 different cancer types, the CXCR4-CXCL12-axis is involved in multiple key processes including proliferation, survival, migration, invasion, and metastasis. Since data on this axis in diffuse large B cell lymphoma (DLBCL) are inconsistent and limited, we comprehensively studied the CXCR4-CXCL12-axis in our DLBCL cohort as well as the effects of CXCR4 antagonists on lymphoma cell lines in vitro. In DLBCL, we observed a 140-fold higher CXCR4 expression compared to non-neoplastic controls, which was associated with poor clinical outcome. In corresponding bone marrow biopsies, we observed a correlation of CXCL12 expression and lymphoma infiltration rate as well as a reduction of CXCR4 expression in remission of bone marrow involvement after treatment. Additionally, we investigated the effects of three CXCR4 antagonists in vitro. Therefore, we used AMD3100 (Plerixafor), AMD070 (Mavorixafor), and WKI, the niacin derivative of AMD070, which we synthesized. WK1 demonstrated stronger pro-apoptotic effects than AMD070 in vitro and induced expression of pro-apoptotic genes of the BCL2-family in CXCR4-positive lymphoma cell lines. Finally, WK1 treatment resulted in the reduced expression of JNK-, ERK1/2- and NF-κB/BCR-target genes. These data indicate that the CXCR4-CXCL12-axis impacts the pathogenesis of DLBCL and represents a potential therapeutic target in aggressive lymphomas.

Operative R0 resection of diffuse large B-cell lymphoma of the pelvis: a case report.

BACKGROUND: Diffuse large B-cell lymphoma is the most common subtype of non-Hodgkin lymphoma with or without involvement of extranodal sites. Rituximab in combination with cyclophosphamide, doxorubicin, vincristine and prednisolone (R-CHOP) therapy represents the current standard therapy, achieving a rather dissatisfying outcome in approximately 30-40% of all cases. CASE PRESENTATION: We present the case of a 43-year-old Austrian woman with an incidentally detected large pelvic mass which was diagnosed as diffuse large B-cell lymphoma. Initially, the lymphoma intraoperatively appeared to be an inoperable conglomerate tumor. Soon, intestinal perforation induced by tumor infiltration occurred, which initiated a closure of the small intestine and application of a jejunal probe and a percutaneous endoscopic gastrotomy tube. Treatment utilizing the gold standard rituximab in combination with cyclophosphamide, doxorubicin, vincristine and prednisolone (R-CHOP) was performed, partly resulting in remission according to radiological follow-up. In view of diagnosis and primary treatment development, the predictive outcome appeared unsound. However, within the procedure of the latest surgical intervention, which was intended to at least reconstruct the intestinal passage in order to improve quality of life, a surgical R0 resection of the residual tumor mass was achieved. CONCLUSIONS: The case presented here reports an unanticipated process of diffuse large B-cell lymphoma, underlining the importance of interdisciplinary cooperation and surgical intervention within the realms of state-of-the-art treatment.

Cytoplasmic location of NR4A1 in aggressive lymphomas is associated with a favourable cancer specific survival.

The nuclear orphan receptor NR4A1 functions as tumour suppressor in aggressive lymphomas by pro-apoptotic genomic and non-genomic effects. Here, we immunohistochemically studied the clinico-pathological relevance of NR4A1 protein expression patterns in a cohort of 60 diffuse large B cell lymphoma (DLBCL) patients and non-neoplastic lymph nodes. We observed a significant association between high cytoplasmic NR4A1 and favourable cancer-specific survival and the germinal centre B cell-like subtype, respectively. Moreover, the percentage of lymphoma cells exhibiting cytoplasmic NR4A1 significantly correlated to those showing cleaved caspase 3. Complementary, functional profiling using gene set enrichment of Reactome pathways based on publicly available microarray data was applied to determine pathways potentially implicated in cytoplasmic localization of NR4A1 and validated by means of semi quantitative real-time PCR. The pathway analysis revealed changes in the ERK1/2 pathway, and this was corroborated by the finding that high cytoplasmic NR4A1 was associated with higher expression of ERK1/2 targets in our cohort. These data indicate that high cytoplasmic NR4A1 is associated with a favourable lymphoma-specific survival and highlights the importance of NR4A1 expression patterns as potential prognostic marker for risk assessment in aggressive lymphomas.