ALK-positive Anaplastic Large Cell Lymphoma Research Articles

Podcast on Emerging Treatment Options for Pediatric Patients with ALK-Positive Anaplastic Large Cell Lymphoma and Inflammatory Myofibroblastic Tumors.

Anaplastic large cell lymphoma (ALCL) and inflammatory myofibroblastic tumor (IMT) are rare cancers observed predominantly in children and young adults. ALCL accounts for 10-15% of all pediatric non-Hodgkin lymphomas and is commonly diagnosed at an advanced stage of disease. In children, 84-91% of cases of ALCL harbor an anaplastic lymphoma kinase (ALK) gene translocation. IMT is a rare mesenchymal neoplasm that also tends to occur in children and adolescents. Approximately 50-70% of IMT cases involve rearrangements in the ALK gene. A combination of chemotherapeutic drugs is typically used for children with ALK-positive ALCL, and the only known curative therapy for ALK-positive IMT is complete surgical resection. Crizotinib, a first-generation ALK inhibitor, was approved in the USA in 2021 for pediatric patients and young adults with relapsed or refractory ALK-positive ALCL; however, its safety and efficacy have not been established in older adults. In 2022, crizotinib was approved for adult and pediatric patients with unresectable, recurrent, or refractory ALK-positive IMT. This podcast provides an overview of ALK-positive ALCL and IMT. We discuss the current treatment landscape, the role of ALK tyrosine kinase inhibitors, and areas of future research.

Current views on the etiology and pathogenesis of ALK-positive anaplastic large cell lymphoma

Current views on the etiology and pathogenesis of ALK-positive anaplastic large cell lymphoma

The Histopathologic Features of Early COVID Pneumonia in a Pediatric Patient: New Insight into the Role of Macrophages

A life-threatening complication of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection is acute respiratory distress syndrome. Our understanding of the pathologic changes in coronavirus disease 2019 (COVID-19) is based almost exclusively on post-mortem analyses of adults. These studies established several hallmarks of SARS-CoV-2 lung infection, including diffuse alveolar damage, microvascular thrombi, and acute bronchopneumonia. We describe a fatal example of COVID pneumonia in a 9-year-old girl who presented with fever 10 months following the diagnosis of ALK-positive anaplastic large cell lymphoma (ALCL). A chest computed tomography scan revealed left upper lobe lung consolidation and nodular airspace disease, and an initial SARS-CoV-2 nasopharyngeal swab (RT-PCR) was negative. A subsequent lung biopsy performed due to concern for relapsed ALCL demonstrated sheets of intra-alveolar and interstitial macrophages, and macrophage-rich fibrinous exudates. Immunohistochemical and in-situ hybridization stains confirmed these macrophages as the predominant SARS-CoV-2-infected cell type. Subsequent RT-PCR testing of upper and lower respiratory tract samples was positive for SARS-CoV-2 infection. Whole genome sequencing confirmed the presence of the B.1.617.2 (Delta) variant. This biopsy illustrates the histopathologic features of early COVID pneumonia in antemortem lung tissue from a pediatric patient, and establishes macrophages as a potential source of SARS-CoV-2 amplification.

Challenges in utilizing ALK expression to distinguish primary cutaneous from systemic anaplastic large cell lymphoma.

Anaplastic large cell lymphoma (ALCL) is a CD30+ peripheral T-cell lymphoma with a clinical spectrum including cutaneous and systemic presentations. While primary cutaneous ALCL (pcALCL) has a favorable prognosis, systemic ALCL (sALCL) has poorer survival outcomes. Expression of anaplastic lymphoma kinase (ALK) by malignant cells has been suggested to distinguish sALCL from pcALCL. However, there have been documented cases of ALK-positive ALCL confined to the skin. The present study reviewed characteristics of published cutaneous ALK-positive ALCL cases to distinguish between these two entities. In 23 identified adults with ALK-positive pcALCL, 26% developed systemic involvement and 74% had skin-limited disease. In 14 pediatric patients, 36% had both cutaneous and systemic involvement and 64% had cutaneous disease only. This analysis revealed that pcALCL and sALCL could not reliably be distinguished by ALK expression or nuclear vs. cytoplasmic localization. Localized treatment with frequent monitoring may be sufficient in ALK-positive pcALCL until there is evidence of progression. Physicians should be aware of the overall spectrum of ALCL, including cutaneous limited disease, systemic disease, disease with NPM-ALK translocation, disease with ALK positivity and disease with skin recurrence.

Variant ALK-fusion positive anaplastic large cell lymphoma (ALCL): A population-based paediatric study of the NHL-BFM study group.

Frequency, distribution and prognostic meaning of ALK-partner genes other than NPM1 in ALK-positive anaplastic large-cell lymphoma (ALCL) are unknown. Forty-nine of 316 ALCL diagnosed in the NHL-BFM study group showed no nuclear ALK expression suggestive of a variant ALK-partner; 41 were analysed by genomic capture high-throughput sequencing or specific RT-PCRs. NPM1::ALK was detected in 13 cases. Among the 28 patients with a non-NPM1::ALK-fusion partner, ATIC (n = 8; 29%) and TPM3 (n = 9; 32%) were the most common. Five of eight patients with ATIC::ALK-positive ALCL relapsed, none of nine with TPM3::ALK. Variant ALK-partners are rare and potentially associated with different prognoses.

Molecular Screening in Anaplastic Lymphoma Kinase–Positive Anaplastic Large Cell Lymphoma: Anaplastic Lymphoma Kinase Analysis, Next-Generation Sequencing Fusion Gene Detection, and T-Cell Receptor Immunoprofiling

Anaplastic lymphoma kinase–positive anaplastic large cell lymphoma (ALK+ ALCL) originates from the T-lineage and is marked by rearrangements of the ALK gene. More than 10 fusion partners with the ALK gene are known, with the most common being the t(2;5)(p23;q35) translocation resulting in the NPM1::ALK fusion. In 10% to 20% of the ALK+ ALCL cases, the ALK gene fuses with various other partners. Modern molecular techniques, especially next-generation sequencing (NGS), have eased the identification of ALK gene fusion partners and have allowed in-depth characterization of the T-cell receptor (TCR) repertoire. We devised a real-time quantitative reverse-transcription polymerase chain reaction to measure the expression of the translocated portion of the ALK gene. Fusion partners for the ALK gene were analyzed using rapid amplification of 5′cDNA ends (RACE) method or NGS. TCR immunoprofiling was performed by amplicon NGS. We studied 96 ALK+ ALCL patients. NPM1::ALK fusion gene was observed in 71 patients, ATIC::ALK in 9, and TPM3::ALK in 3. CLTC::ALK, MYH9::ALK, and RNF213::ALK fusions were identified in 2 patients each. We also discovered the TPM4::ALK and SATB1::ALK fusion genes, plus the following 2 previously unidentified ALK+ ALCL fusions: SQSTM1::ALK and CAPRIN1::ALK. High expression of the translocated ALK gene segment was observed in all 93 analyzed samples. TCR testing was conducted on 23 patients with available DNA. In 18 (78%) patients, we discerned at least one (ranging from 1 to 4) clonal TCR rearrangement. In 59% of the patients, clonal TCR beta junctions corresponded with sequences previously observed in both healthy donors and under various pathological conditions. Reverse-transcriptase quantitative detection of ALK expression is a fast and reliable method for both diagnosing and monitoring treatment response in ALK+ ALCL patients, irrespective of the ALK gene translocation. NGS reveals new ALK translocation partners. Both malignant and reactive TCR repertoires in ALK+ ALCL patients are unique and do not consistently occur among different patients.

[Successful bridging therapy with alectinib prior to allogeneic stem cell transplantation for refractory ALK-positive anaplastic large cell lymphoma].

Although alectinib is effective for relapsed or refractory ALK-positive anaplastic large cell lymphoma (ALCL) and has a favorable safety profile, its role as a bridging therapy for allogeneic hematopoietic stem cell transplantation (allo-HSCT) and the role of allo-HSCT itself in this setting are unknown. A 35-year-old man with ALK-positive ALCL experienced relapse after first-line therapy with CHOP. Brentuximab vedotin led to partial response and high-dose chemotherapy combined with autologous HSCT was performed. However, disease progressed 15 months after transplantation, and alectinib was initiated. Complete response (CR) was achieved after three months of treatment, and alectinib was continued for 5 months. After cessation of alectinib, allogeneic bone marrow transplantation from an HLA 1-locus mismatched unrelated donor was performed after conditioning with fludarabine, busulfan, and total body irradiation. GVHD prophylaxis consisted of tacrolimus and short-term methotrexate. The post-transplant course was unremarkable except for grade I acute GVHD. The lymphoma has not recurred for 2 years after allo-HSCT without resuming alectinib. The clinical course of our case suggests that alectinib bridging therapy and allo-HSCT are effective in relapsed/refractory ALK-positive ALCL.

Strategy for Pediatric Patients with Relapsed or Refractory Anaplastic Lymphoma Kinase-Positive Anaplastic Large Cell Lymphoma: A Review.

Anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) is an aggressive T-cell lymphoma characterized by large T-cells with strong CD30 and ALK expression. Although conventional chemotherapy is effective in most patients, approximately 30% experience a relapse or refractory disease and have a poor prognosis. Several risk factors associated with poor prognosis have been identified in pediatric ALK-positive ALCL. These include morphological patterns with the small cell variant or lymphohistiocytic variant, leukemic presentation, the presence of minimal disseminated disease, or involvement of the central nervous system. Relapsed or refractory ALK-positive ALCL is often resistant to conventional chemotherapy; therefore, salvage therapy is required. In recent years, targeted therapies such as ALK inhibitors and brentuximab vedotin (BV) have been developed. ALK inhibitors block the continuous activation of ALK kinase, a driver mutation that leads to cell proliferation in ALK-positive ALCL. Additionally, BV is an antibody-drug conjugate that targets CD30-positive cells. Both ALK inhibitors and BV have displayed dramatic effects in chemoresistant ALK-positive ALCL. Weekly vinblastine treatment and hematopoietic stem cell transplantation have also been reported to be effective therapies. This article reviews pediatric ALK-positive ALCL, focusing on risk factors and treatment strategies for pediatric patients with relapsed or refractory ALK-positive ALCL.

Prognostic Impact of Minimal Disseminated Disease (MDD) and Minimal Residual Disease (MRD) in Chinese Pediatric Patients with ALK-Positive Anaplastic Large Cell Lymphoma (ALCL)

# Keyan Yang and Jing Yang contribute equally to this article. * Corresponding to both Qinlong Zheng (zhengql@gobroadhealthcare.com) and Yonghong Zhang (zhangyongh@gobroadhealthcare.com) Backgrounds: Anaplastic lymphoma kinase positive anaplastic large cell lymphoma (ALK+ALCL) is characterized by the occurrence of the ALK fusion and subsequently ALK fusion kinase protein expression. It has been reported that minimal disseminated disease (MDD) and minimal residual disease (MRD) detected by RQ-PCR are independent prognostic factors. Purpose & Methods: To explored the prognostic roles of MDD and MRD in Chinese pediatric patients with ALCL, we conduct a retrospective study in a cohort of 204 Chinese children and adolescent ALK+ALCL patients treated at multiple centers of the China Network of Childhood Lymphoma (CNCL). The median follow-up time was 39 months (95%CI: 34-44.7). MDD level as ALK fusion copy number was measured by quantitative RT-PCR at the initial diagnosis. Based on the Overall Survival (OS) data, cut-off values of 1.63 in peripheral blood (PB) and 1.43 in bone marrow (BM) were determined by using the maximally selected rank statistics, with the c-index values of 0.904 in PB and 0.895 in BM. Results: The prevalence of MDD in PB and/or BM of Chinese pediatric patients with ALK+ALCL was 24.8%, while the MDD level were significantly correlated between PB and BM (R=0.8, p<2.2e-16). In addition, the 3-year OS (PB, 87.8% vs. 100%; BM, 87.9% vs. 100%) and EFS (PB, 73.2% vs. 94.8%; BM, 80.0% vs. 93.2%) were revealed with significant difference, when analyzed by MDD level. The combined analyses of both MDD level (with the same cut-off value) and MRD results (positive vs. negative), either after 1 st course of treatment (MRD1) or 2 nd course of treatment (MRD2), indicated the further poor prognosis, both in 3-year OS (PB, MRD1, 64.8% vs. 100%, MRD2, 72.9% vs. 100%; BM, MRD1, 64.8% vs. 100%, MRD2, 68.8% vs. 100%) and EFS (PB, MRD1, 40.0% vs. 95.3%, MRD2, 45.0% vs. 95.1%; BM, MRD1, 40.0% vs. 94.7%, MRD2, 35.7% vs. 94.4%). Conclusion: Summary, in this work, MDD level detected by quantitative RT-PCR was revealed as a strong factor in prognostic evaluation of Chinese children and adolescent patients with ALK+ALCL, which showed its important role in clinical detection at initial diagnostic. In future, the further validation work could be carried out in different cohort of ALK+ALCL patients, even with larger enrolled population size and longer follow-up time.

Red Cell Distribution Width-to-Albumin Ratio Is a Simple but Robust Prognostic Biomarker in Peripheral T-Cell Lymphoma

Background: Red cell distribution width (RDW) is the difference in the volume and size of erythrocytes. High RDW has been identified as a worse prognostic factor in various diseases, including sepsis, cerebrovascular accidents, and diverse cancers. More recently, RDW-to-albumin ratio (RAR) is a comprehensive biomarker combining inflammation and nutrition status that better reflects a patient's frailty. However, little is known about its prognostic relevance in peripheral T-cell lymphoma (PTCL), with only one publication focusing on RDW (Castro et al.). Methods: This retrospective analysis included consecutive patients with newly diagnosed PTCL between 2007 and 2023 at Kameda Medical Center. Extranodal NK/T-cell lymphoma, adult T-cell leukemia/lymphoma, and ALK-positive anaplastic large cell lymphoma were excluded due to distinct prognosis and treatment strategies. The RDW coefficient of variation (RDW-CV) was assessed prior to treatment and calculated using the following formula: 1 standard deviation of mean corpuscular volume (MCV) divided by MCV, multiplied by 100. Receiver operating curve (ROC) analysis was used to determine the optimal cutoff value of RDW-CV and RAR for 2-year outcomes. Survival analyses were conducted using Kaplan-Meier curves with log-rank tests, and Cox proportional hazard models were used for univariate and multivariate analyses. Results: In total, 115 patients were included in this analysis. The median age was 74 years (range 45-93), with male predominance (60.8%). Sixty-five patients (56.5%) were initially treated with the CHOP regimen, while 29 patients (25.2%) received more intensive chemotherapy. The most common disease subtype was PTCL-not otherwise specified (49.5%), followed by angioimmunoblastic lymphoma (40.0%). The median RDW-CV and RAR were 14.8 (range 12.2-21.5) and 4.61 (range 2.6-9.8), respectively. The RDW-CV was significantly correlated with levels of hemoglobin (R = -0.4), albumin (R = - 0.59), and lactate dehydrogenase (R = 0.27) (all P < 0.05). ROC curve analysis for 2-year survival revealed a higher area under the curve (AUC) for RAR (0.79) compared to RDW (0.74), with cutoff values of 4.4 and 14.1, respectively (Figure 1). Using this cutoff value, patients with high RAR had significantly worse overall survival (OS) and progression free survival (PFS) than those without (2-year OS rate: 82.5% vs. 35.1%, Figure 2; 2-year PFS rate: 54.8% vs. 27.9%, P <0.001). On multivariate analysis, high RAR was associated with a significantly worse PFS (hazard ratio [HR] =1.89 [95% confidence interval 1.15-3.11], P =0.01) and OS (HR=3.02 [1.66-5.50], P <0.001) independent of the international prognostic index (IPI), dose reduction of chemotherapy and lymphoma subtype. Conclusion: We demonstrated that RAR improved the prognostic stratification compared to RDW-CV alone. Additionally, baseline high RAR was identified as a simple but robust prognostic factor independently associated with IPI category and treatment intensity in PTCL patients.

Circulating Tumor DNA (ctDNA) for Plasma Genotyping and Disease Monitoring in ALK-Positive Anaplastic Lymphoma (ALK+ALCL): A Proof of Concept Study

Introduction Circulating tumor DNA (ctDNA) detection has not been reported yet in ALK-positive anaplastic large cell lymphoma (ALK+ALCL), a rare aggressive non-Hodgkin lymphoma with a peak incidence in children, adolescents and young adults. In this study, we aimed to evaluate whether ctDNA can be detected, characterized and used to monitor minimal residual disease (MRD) in ALK+ALCL. Patients and Methods Plasma samples were collected from 23 French patients diagnosed with ALK+ALCL between November 2020 and March 2023. Based on cell-free DNA (cfDNA) extracted from plasma, we performed shallow whole genome sequencing (shWGS) and a comprehensive genomic profiling (CGP) of more than 500 genes covered at a median depth of over 3000 unique reads to assess ctDNA content. In this study, we defined samples as positive if they had a tumor fraction over 3%, evaluated by shWGS analysis, or if ALK rearrangements were identified using CGP. Additionally, ALK rearrangement genomic breakpoint were defined by CGP analysis. For each patient, specific digital droplet PCR (ddPCR) assays were designed based on the identified breakpoints to monitor ctDNA content during the ALK+ALCL disease follow-up. Results The median age of patients at the time of diagnosis was 13 years (range: 4-54). Sixteen patients, (69.6%) received at least one ALK tyrosine kinase inhibitor (TKI). A total of 80 plasma samples were collected at various time points from the 23 patients, with a median of 3 samples per patient (range: 1 - 20). Four samples failed for DNA extraction, resulting in 76 samples available for molecular analysis Of the 76 samples, 43 (56.6%) were analyzed using shWGS, 19 (25%) using CGP among which, 14 were analyzed using both techniques. CGP was found to be a more sensitive method for detecting ctDNA in ALK+ALCL compared to shWGS, with 12 out of 14 samples (85.7%) tested positive with CGP, compared to 5 out of 14 samples (35.7%) with shWGS (p<0.01). Of the 19 samples tested with CGP, ALK rearrangement was identified in 14 samples (73.7%), with NPM1:: ALK fusion detected in 11 samples, and ATIC:: ALK, TRAF1:: ALK and EEF1G:: ALK detected in one sample each. The average tumor mutational burden was low, with 5.3 mutations per megabase (mut/Mb) (range: 0-14.5 mut/Mb). No microsatellite instability was detected. Amplification of MDM4 and MYC genes was observed in three patients each. ANKRD26 was the most frequently mutated gene in the study, with four patients affected. LRP1B, epigenetic modifiers such as EP300 and KMT2A, and TP53 were mutated in three patients each. Interestingly, CGP allowed the identification of the ALK:c.3520T>C;p.(Phe1174Leu) mutation in a plasma sample collected during disease progression while the patient was on long lasting crizotinib therapy. Finally, we monitored MRD, based on ctDNA detection in 49 samples from 12 patients using ddPCR assays. Our results were compared with the established gold standard for MRD monitoring in ALK+ALCL, i.e. RT-PCR on circulating cells performed on the same samples. The ddPCR assay showed a 87% sensitivity, 100% specificity, 100% positive predictive value, and 83% negative predictive value. However, four samples had false-negative results due to pre-analytical sampling issues. These samples had been stored at room temperature without undergoing centrifugation for more than 24 hours. Conclusion To date, this study is the first to report on the feasibility and clinical value of ctDNA for the management of ALK+ALCL patients. CGP demonstrated high sensitivity in detecting ctDNA, identifying the genomic breakpoint within the ALK gene and, for the first time in ALK+ALCL, detecting resistance mutations to ALK TKI. Additionally, our unique patient-specific ddPCR approach was proven to be a cost-effective method for MRD monitoring. Altogether, these findings serve as a proof-of-concept for the development of ctDNA techniques in the clinical management of ALK+ALCL.

Distinct Subtypes of Chemotherapy-Resistant Systemic ALK-Positive Anaplastic Large Cell Lymphoma Demonstrate Long-Term Complete Remissions to Imatinib

Background Platelet-derived growth factor receptor (PDGFR) is expressed in nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) positive anaplastic large cell lymphomas (ALCL ALK+). Our previous preclinical research suggested that PDGFR blockade by the Abl/c-Kit/PDGFR kinase inhibitor imatinib could be an effective treatment strategy for ALCL ALK+. An indicator patient whose ALCL cells expressed PDGFR and who failed three treatment lines (including autologous stem cell transplantation) achieved complete remission (CR) with imatinib. Methods We treated 6 relapsed/refractory (r/r) ALK+ ALCL patients with imatinib, 4 of which within the prospective clinical trial, EudraCT No.: 2013-003505-26. Median follow-up was 40 months (160 weeks, range 4 - 428). Patients were characterized by whole exome sequencing, bisulfite sequencing, RNA-sequencing and immunological profiling. Whole exome sequencing data were integrated and compared to 32 additional ALK+ ALCL patients (Larose et. al., Haematologica, 2021; Creszenzo et al., Cancer Cell 2015; Mologni et al. (unpublished). Results 5-year progression-free survival (PFS) was 67%. 4 out of 6 patients achieved a CR that was maintained throughout the follow-up of 3.3 - 8.9 years. Lymphoma cells of the non-responding patients did not express PDGFRA/B as confirmed by immunohistochemistry and RNA-scope (panel figure A). Cytoplasmic co-expression of both, ALK and PDGFRA/B, in ALCL tumor cells was associated with complete response to imatinib in ALK+ ALCL patients. Methylation profiling confirmed a differentially activated PDGFR axis between responders and non-responders and identified a specific protein kinase profile that included a significant inflammatory upregulation of HGFAC, VEGFa, and TNFa in serum cytokine profiling. The transcriptional differential gene expression includes an upregulation of genes of GO:0045859 (regulation of protein kinase activity) in non-resonders. Ident pathologic variants resulting in amino-acid changes were detected in non-responders in mutated genes linked to kinase activity ( TBC1D28 E56A), protein processing ( EMC1 S323T: cosmicV64345386 and EMC1S325N: cosmicV100916421; and GOLGA8S) and cytokine signaling ( IFNL2, ZFYVE19). The imatinib-resitance profile involving mutations in EMC1 and GOLGA8S could be detected at a frequency of 6/32 (19%) in an independent reference cohort of r/r ALK+ALCL (panel figure B). Exclusive mutations in PPP1R13B linked to p53-pathway were found in all responders. PDGFRA mutations with low allele frequencies (2-5%) were identified soley in imatinib-responders. Additionally, non-responders were characterized by an exclusive mutational signature linked to vesicular endocytosis and cytokine signaling as a resistance mechanism to pan-kinase inhibitor imatinib. Conclusion PDGFRA/B expression in tumour cells of therapy-resistant ALK-positive ALCL patients can discriminate genetically and functionally distinct lymphoma subgroups that are directly related to long-term treatment response to kinase inhibitor imatinib. Our data suggests that significant imatinib responses may be achieved in more than 80% of chemotherapy-resistant ALK+ ALCL cases.

Genome-Wide CRISPR Screen Identifies ZNF451 Regulating Sensitivity to Topoisomerase 2 Inhibitors in Peripheral T-Cell Lymphoma Cells

Introduction: Despite the recent therapeutic developments for peripheral T-cell lymphomas (PTCLs), their prognosis remains dismal. Topoisomerase 2 inhibitors (TOP2i), which increase the amount of TOP2-DNA covalent complex and block DNA double-strand break repair, have long been used as key drugs in the treatment of PTCLs. The molecular mechanisms underlying sensitivity to TOP2i remain to be fully elucidated. Methods: To elucidate the cell-intrinsic genes affecting TOP2i sensitivity in PTCL cells, we performed whole-genome loss-of-function CRISPR screenings in adult T-cell leukemia/lymphoma (ATLL) cell lines. ST1 and KK1 cells were transduced with the Brunello CRISPR knockout pooled library targeting 19,114 genes (4 sgRNAs/gene) followed by puromycin selection. The transduced cells were then treated with etoposide (ETP), doxorubicin (DOX) or DMSO control for 8 days. The MAGeCK algorithm was used to rank the sgRNAs responsible for TOP2i sensitivity. Among the top 500 enriched genes, we further selected the those with at least 2 sgRNAs with a log2 fold change (TOP2i/DMSO) < -0.5 or >0.5 in both ST1 and KK1 cells as genes whose knockout conferred TOP2i sensitivity or resistance, respectively. Results: Using the whole genome loss-of-function CRISPR screen, we identified 3 genes and 2 genes whose knockout conferred ETP sensitivity and resistance, respectively. TOP2A, a known ETP target, was ranked as a top gene for ETP resistance, confirming the reliability of our screenings (Fig. 1). In the same way we also extracted 3 genes whose knockout conferred DOX sensitivity. Interestingly, zinc finger protein 451 (ZNF451) was identified as an overlapping gene whose knockout conferred sensitivity in both screens for ETP and DOX. ZNF451 is an E3 SUMO ligase and was previously reported to be an endogenous DNA repair factor for TOP2i-induced DNA double-strand breaks (Schellenberg et al. Science 2017). The role of ZNF451 in PTCL cells has not been previously reported, prompting us to focus on ZNF451 in further analyses. For a confirmatory experiments, we transduced sgRNAs targeting ZNF451 (sgZNF451) in ATLL cell lines. To see the knockout efficiencies of the sgZNF451, we performed immunoblot analysis by using anti-ZNF451 antibody and found three bands with different levels of reduction. To ensure whether the bands detected by the anti-ZNF451 antibody represented endogenous ZNF451 protein, we engineered the ATLL cell line with an HA-tag at the 5' UTR of the endogenous ZNF451 gene locus by CRISPR-mediated knock-in. Immunoblot analysis of sgZNF451-transduced engineered cells expressing HA-tag-ZNF451 by using anti-HA antibody showed almost the same pattern of the bands as shown in the blot by anti-ZNF451 antibody. Thus, we confirmed that sgZNF451 worked efficiently and concluded that post-transcriptional modification affected the stability of ZNF451 protein in ATLL cells. Next, we investigated the role of ZNF451 on cell viability. While sgZNF451-transduced ATLL cells did not differ from control sgRNA-transduced cells in terms of cellular proliferation under normal culture conditions, sgZNF451-transduced ATLL cells showed increased sensitivity to both ETP and DOX compared to control cells with statistical significance, confirming our screening results (Fig. 2). Importantly, sgZNF451-mediated sensitization to ETP and DOX was found not only in ATLL cells but also in other PTCL cell lines including ALK-positive and ALK-negative anaplastic large cell lymphoma (ALCL). Mechanistically, apoptosis and G2/M cell cycle arrest were induced at significantly higher frequencies by ETP treatment in ZNF451 knocked out cells compared to control cells. Given the role of ZNF451 in TOP2i sensitivity in PTCL cells, we investigated whether ZNF451 expression levels stratify the prognosis of PTCL patients treated with CHOP-like regimens. To test this, FFPE samples from 45 PTCL-NOS patients were used for Q-PCR analysis of ZNF451 mRNA but we did not find any correlation between the ZNF451 expression and prognosis. Conclusions: We performed unbiased genome-wide CRISPR/Cas9 library screens and identified ZNF451 as an important regulator of sensitivity to TOP2i in PTCL cells. Further studies are needed to determine whether measuring ZNF451 protein levels can be used as a biomarker in PTCL patients who are treated with TOP2i.

Past, present and future therapeutic approaches in nodal peripheral T-cell lymphomas.

Peripheral T-cell lymphomas (PTCL) encompass over 30 different entities and although they share post-thymic T- or NK-cell derivation, the disease biology and genomic landscape are very diverse across subtypes. In Western populations, nodal PTCL are the most frequently encountered entities in clinical practice and although important achievements have been made in deciphering the underlying biology and in therapeutic advances, there are still large gaps in disease understanding and clinical scenarios in which controversy over best practice continues. CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone)- based chemotherapy continues to be the 'standard' treatment, with the addition of brentuximab vedotin (BV) in the combination CHP (cyclosphosphamide, doxorubicin, prednisone)-BV representing a new treatment paradigm in CD30+ PTCL although its benefit is less certain in the non-anaplastic large cell lymphoma subtypes. Given the high risk of relapse, consolidative autologous stem cell transplant is considered in nodal PTCL, outside of ALK-positive anaplastic large cell lymphoma; however, in the absence of a randomized controlled trials, practices vary. Beyond CHP-BV, most study activity has focused on adding a novel agent to CHOP (i.e., CHOP + drug X). However, with high complete remission rates observed with some novel therapy combinations, these regimens are being tested in the front-line setting, with a particular rationale in follicular helper T-cell lymphomas which have a clear sensitivity to epigenetic modifying therapies. This is well exemplified in the relapsed/refractory setting in which rational combination therapies are being developed for specific subtypes or guided by underlying biology. Taken together, we have finally moved into an era of a more personalized approach to the management of nodal PTCL.

A Combination of Alectinib and DNA-Demethylating Agents Synergistically Inhibits Anaplastic-Lymphoma-Kinase-Positive Anaplastic Large-Cell Lymphoma Cell Proliferation.

The recent evolution of molecular targeted therapy has improved clinical outcomes in several human malignancies. The translocation of anaplastic lymphoma kinase (ALK) was originally identified in anaplastic large-cell lymphoma (ALCL) and subsequently in non-small cell lung carcinoma (NSCLC). Since ALK fusion gene products act as a driver of carcinogenesis in both ALCL and NSCLC, several ALK tyrosine kinase inhibitors (TKIs) have been developed. Crizotinib and alectinib are first- and second-generation ALK TKIs, respectively, approved for the treatment of ALK-positive ALCL (ALK+ ALCL) and ALK+ NSCLC. Although most ALK+ NSCLC patients respond to crizotinib and alectinib, they generally relapse after several years of treatment. We previously found that DNA-demethylating agents enhanced the efficacy of ABL TKIs in chronic myeloid leukemia cells. Moreover, aberrant DNA methylation has also been observed in ALCL cells. Thus, to improve the clinical outcomes of ALK+ ALCL therapy, we investigated the synergistic efficacy of the combination of alectinib and the DNA-demethylating agent azacytidine, decitabine, or OR-2100 (an orally bioavailable decitabine derivative). As expected, the combination of alectinib and DNA-demethylating agents synergistically suppressed ALK+ ALCL cell proliferation, concomitant with DNA hypomethylation and a reduction in STAT3 (a downstream target of ALK fusion proteins) phosphorylation. The combination of alectinib and OR-2100 markedly altered gene expression in ALCL cells, including that of genes implicated in apoptotic signaling, which possibly contributed to the synergistic anti-ALCL effects of this drug combination. Therefore, alectinib and OR-2100 combination therapy has the potential to improve the outcomes of patients with ALK+ ALCL.

[Primary central nervous system ALK-positive anaplastic large cell lymphoma: a clinicopathological analysis of four cases].

[Primary central nervous system ALK-positive anaplastic large cell lymphoma: a clinicopathological analysis of four cases].

Nuclear NPM-ALK Protects Myc from Proteasomal Degradation and Contributes to Its High Expression in Cancer Stem-Like Cells in ALK-Positive Anaplastic Large Cell Lymphoma.

In ALK-positive anaplastic large cell lymphoma (ALK+ALCL), a small subset of cancer stem-like (or RR) cells characterized by high Myc expression have been identified. We hypothesize that NPM-ALK contributes to their high Myc expression. While transfection of NPM-ALK into HEK293 cells effectively increased Myc by inhibiting its proteosomal degradation (PD-Myc), this effect was dramatically attenuated when the full-length NPM1 (FL-NPM1) was downregulated using shRNA, highlighting the importance of the NPM-ALK:FL-ALK heterodimers in this context. Consistent with this concept, immunoprecipitation experiments showed that the heterodimers are abundant only in RR cells, in which the half-life of Myc is substantially longer than the bulk cells. Fbw7γ, a key player in PD-Myc, is sequestered by the heterodimers in RR cells, and this finding correlates with a Myc phosphorylation pattern indicative of ineffective PD-Myc. Using confocal microscopy and immunofluorescence staining, we found that the fusion signal between ALK and FL-NPM1, characteristic of the heterodimers, correlates with the Myc level in ALK+ALCL cells from cell lines and patient samples. To conclude, our findings have revealed a novel oncogenic function of NPM-ALK in the nucleus. Specifically, the NPM-ALK:FL-NPM1 heterodimers increase cancer stemness by blocking PD-Myc and promoting Myc accumulation in the cancer stem-like cell subset.

ALK-positive anaplastic large cell lymphoma in adults.

ALK-positive anaplastic large cell lymphoma (ALCL) represents approximately 6-7% of the mature T-cell lymphomas. This subtype contains a translocation between the ALK gene on chromosome 2 and one of several other genes that together form an oncogene. The most frequent translocation is t(2;5) which combines ALK with NPM1. This lymphoma has a median age of 34 years, is more common in males, and is in advanced stage at the time of diagnosis in most patients. ALK-positive ALCL is the most curable of the peripheral T-cell lymphomas. The CHOP regimen has been most frequently used, but results are improved with the substitution of brentuximab vedotin for vincristine (BV-CHP) and the addition of etoposide (CHOEP), with BV-CHP being favored. Salvage therapies include allogeneic or autologous bone marrow transplantation, BV, if not used as part of the primary therapy, and ALK inhibitors. The latter are very active and likely to be incorporated into the primary therapy.

[Gastrointestinal ALK-positive anaplastic large cell lymphoma: a clinicopathological analysis of five cases].

Objective: To investigate the clinicpathological characteristics of ALK-positive anaplastic large cell lymphoma (ALCL) of the gastrointestinal tract, and to discuss its diagnosis and differential diagnosis. Methods: Five cases of gastrointestinal ALK-positive ALCL diagnosed and treated in Xijing Hospital of the Fourth Military Medical University, between 2011 and 2019 were collected. There were three male and two female patients, aged 5-42 years (mean 25 years). These patients clinically presented with fever and night sweats, weight loss, abdominal pain, abdominal mass, ulcers, bleeding, or intestinal obstruction, and underwent surgical resection of the tumors or endoscopic biopsy. The clinical manifestations, auxiliary examinations, histopathological characteristics, immunophenotypes and genetic alterations were analyzed. Results: In this cohort, one case was common type, two cases were monomorphic variant of common type, and two cases were small cell variant. The tumor cells in all cases expressed ALK, CD30, and one or more T lymphocyte markers, while all the markers of B lymphocyte and plasmacyte were negative. Clonality analysis showed that two cases had clonal T cell receptor (TCR) and immunoglobulin (Ig) gene rearrangement, one case had no clonal TCR but Ig gene rearrangement, and one case had no clonal TCR and Ig gene rearrangements. During the 4 to 67 months' follow-up, two patients died of the disease, two were alive with free of disease and one had a relapse. Conclusions: ALK-positive ALCL of the gastrointestinal tract is extremely rare, and has poor prognosis. Lymphoma originating from this site with CD30 and ALK-positive phenotypes may be considered to be ALCL; however differentiation from other tumors that had anaplastic features, expressed CD30 and or ALK, in particular, ALK positive large B-cell lymphoma is necessary.

Teaching NeuroImage: Branching Dura Mater in Primary Central Nervous System, ALK-Positive, Anaplastic Large Cell Lymphoma.

Teaching NeuroImage: Branching Dura Mater in Primary Central Nervous System, ALK-Positive, Anaplastic Large Cell Lymphoma.