STAT3 couples activated tyrosine kinase signaling to the oncogenic core transcriptional regulatory circuitry of anaplastic large cell lymphoma

Anaplastic large cell lymphoma (ALCL) is an aggressive, CD30+ T cell lymphoma of children and adults. ALK fusion transcripts or mutations in the JAK-STAT pathway are observed in most ALCL tumors, but the mechanisms underlying tumorigenesis are not fully understood. Here, we show that dysregulated STAT3 in ALCL cooccupies enhancers with master transcription factors BATF3, IRF4, and IKZF1 to form a core regulatory circuit that establishes and maintains the malignant cell state in ALCL. Critical downstream targets of this network in ALCL cells include the protooncogene MYC, which requires active STAT3 to facilitate high levels of MYC transcription. The core autoregulatory transcriptional circuitry activity is reinforced by MYC binding to the enhancer regions associated with STAT3 and each of the core regulatory transcription factors. Thus, activation of STAT3 provides the crucial link between aberrant tyrosine kinase signaling and the core transcriptional machinery that drives tumorigenesis and creates therapeutic vulnerabilities in ALCL.

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.

Spatially Resolved Transcriptomes of CD30+-Transformed Mycosis Fungoides and Cutaneous Anaplastic Large-Cell Lymphoma

Mycosis fungoides with large-cell transformation (MF-LCT) occurs in a minor proportion of aggressive lesions, which express CD30 similar to primary cutaneous anaplastic large-cell lymphoma (pcALCL). We investigated the differences in spatially resolved transcriptome profiles of MF-LCT and pcALCL using CD30 morphology markers and 28 and 24 regions of interest (ROIs) in MF-LCT and pcALCL, respectively. Differentially expressed genes, pathway analysis, and immune-cell deconvolution by selective analysis of CD30-positive tumor cells and CD30-negative extratumoral areas were undertaken. In CD30-positive ROIs of MF-LCT, 190 differentially expressed genes were upregulated (29 were directly or indirectly associated with extracellular matrix remodeling), whereas 255 differentially expressed genes were downregulated, compared with those of pcALCL. Except for cornified envelope formation and keratinization, all six pathways enriched in CD30-positive ROIs of MF-LCT were associated with extracellular matrix remodeling. In CD30-positive ROIs in MF-LCT compared with those in pcALCL, immune-cell deconvolution revealed significantly increased fibroblasts and M2 macrophages (P = 0.012 and P = 0.023, respectively) but decreased M1 macrophages (P = 0.031). In CD30-negative ROIs in MF-LCT compared with those in pcALCL, memory B (P = 0.021), plasma (P = 0.023), and CD8 memory T (P = 0.001) cells significantly decreased, whereas regulatory T cells (P = 0.024) increased. Predomination of extracellular matrix remodeling pathways and immunosuppressive microenvironment in MF-LCT indicates pathophysiological differences between MF-LCT and pcALCL.

Extranodal NK/T-Cell Lymphoma Predominantly Composed of Anaplastic Cells: A Frequently Misdiagnosed and Highly Aggressive Variant

Extranodal NK/T-cell lymphoma (ENKTL) is a non-Hodgkin lymphoma associated with the Epstein-Barr virus that primarily affects individuals in East Asia and indigenous populations in Central and South America. Morphologically, ENKTL typically consists of medium-sized cells or a combination of small and large cells. This report presents 10 cases characterized by predominantly anaplastic cells with diffuse expression of CD30, resembling anaplastic lymphoma kinase-negative anaplastic large cell lymphoma (ALK-negative ALCL) and demonstrating highly aggressive behavior. The cohort included 9 males and 1 female, ranging in age from 29 to 65 years (median age: 47 y). Eight patients presented with nasal disease, while 2 had non-nasal disease. Five patients had stage I/II disease, and the remaining 5 had stage III/IV disease. Morphologically, necrosis was observed in 9 cases, angiocentric-angiodestructive growth in 3 cases, and pseudoepitheliomatous hyperplasia in 2 cases. Anaplastic cells predominated in all cases, with some displaying eccentric, horseshoe-shaped, or kidney-shaped nuclei (referred to as "Hallmark" cells). The morphology profile was monomorphic in 3 cases and polymorphic in 7 cases. Immunohistochemically, all cases tested positive for cytotoxic granule markers (TIA1 and granzymeB) and Epstein-Barr virus-encoded RNA. Cytoplasmic expression of CD3ε and CD56 was observed in 9 of 10 cases. Interestingly, most cases (7 of 8) exhibited variable expression of MuM1, ranging from 10% to 90%. All cases showed diffuse positivity for CD30 but were negative for ALK, resulting in 3 cases being initially misdiagnosed as ALK-negative ALCL. Compared with nonanaplastic cases, anaplastic cells predominant ENKTL had a significantly higher frequency of "B" symptoms, bone marrow involvement, hemophagocytic lymphohistiocytosis, and higher Ki67 proliferative index. These findings provide valuable information for pathologists, expanding their understanding of the cytologic spectrum of ENKTL. This rare variant of ENKTL, characterized by the predominance of anaplastic cells and diffuse CD30 expression, exhibits high aggressiveness and should be differentiated from ALK-negative ALCL. Awareness of this uncommon variant is crucial in preventing misdiagnosis and ensuring the timely initiation of therapy.

Detection of TRAF1-ALK fusion in skin lesions of systemic ALK+ anaplastic large cell lymphoma initially involving the skin and the draining lymph node

A case of cytoplasmic anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) initially involving the skin in a 44-year-old Japanese female is reported. The patient had a hemorrhagic erythematous tumor on the right thigh without any systemic symptoms. Pathology showed diffuse infiltration of CD30-positive anaplastic large cells positive for epithelial membrane antigen and cytoplasmic ALK. The right inguinal lymph node showed infiltration of tumor cells in the marginal sinus. Only 2 weeks after radiation therapy, the patient developed multiple subcutaneous nodules and lung involvement. Even after subsequent multichemotherapy sessions, cutaneous recurrence occurred. Literature review of cytoplasmic ALK-positive ALCL initially involving in the skin revealed that skin lesions were mostly seen in the extremities and that half of the cases developed extracutaneous lesions. Radiation and chemotherapy were effective for most cases. Inverse RT-PCR identified a tumor necrosis factor receptor-associated factor (TRAF)1-ALK fusion in our case. Most reported cases with this translocation experienced repeated changes in chemotherapy, suggesting poorer prognosis. Although ALK-positive ALCL generally responds well to chemotherapy, the presence of a TRAF1-ALK fusion may suggest resistance to treatment. Detection of fusion partners of ALK is important for predicting clinical courses and deciding treatment options.

Pathobiology of nodal peripheral T-cell lymphomas: current understanding and future directions

Predominantly nodal is the most common clinical presentation of peripheral T- (and NK-) cell lymphomas (PTCL), which comprise three main groups of diseases: (i) systemic anaplastic large cell lymphomas (ALCL), whether positive or negative for anaplastic lymphoma kinase (ALK); (ii) follicular helper T-cell lymphomas (TFHL); and (iii) PTCL, not otherwise specified (NOS). Recent advances in the genomic and molecular characterization of PTCL, with enhanced understanding of pathobiology, have translated into significant updates in the latest 2022 classifications of lymphomas. ALK-negative ALCL is now recognized to be genetically heterogeneous, with identification of DUSP22 rearrangements in approximately 20-30% of cases, correlated with distinctive pathological and biological features. The notion of cell-of-origin as an important determinant of the classification of nodal PTCL is best exemplified by TFHL, considered as one disease or a group of related entities, sharing oncogenic pathways with frequent recurrent epigenetic mutations as well as a relationship to clonal hematopoiesis. Data are emerging to support that a similar cell-of-origin concept might be relevant to characterize meaningful subgroups within PTCL, NOS, based on cytotoxic and/or Th1 versus Th2 signatures. The small group of primary nodal Epstein-Barr virus-positive lymphomas of T- or NK-cell derivation, formerly considered PTCL, NOS, is now classified separately, due to distinctive features, and notably an aggressive course. This review summarizes current knowledge of the pathology and biology of nodal-based PTCL entities, with an emphasis on recent findings and underlying oncogenic mechanisms.

Chimeric kinase ALK induces expression of NAMPT and selectively depends on this metabolic enzyme to sustain its own oncogenic function

As we show in this study, NAMPT, the key rate-limiting enzyme in the salvage pathway, one of the three known pathways involved in NAD synthesis, is selectively over-expressed in anaplastic T-cell lymphoma carrying oncogenic kinase NPM1::ALK (ALK + ALCL). NPM1::ALK induces expression of the NAMPT-encoding gene with STAT3 acting as transcriptional activator of the gene. Inhibition of NAMPT affects ALK + ALCL cells expression of numerous genes, many from the cell-signaling, metabolic, and apoptotic pathways. NAMPT inhibition also functionally impairs the key metabolic and signaling pathways, strikingly including enzymatic activity and, hence, oncogenic function of NPM1::ALK itself. Consequently, NAMPT inhibition induces cell death in vitro and suppresses ALK + ALCL tumor growth in vivo. These results indicate that NAMPT is a novel therapeutic target in ALK + ALCL and, possibly, other similar malignancies. Targeting metabolic pathways selectively activated by oncogenic kinases to which malignant cells become "addicted" may become a novel therapeutic approach to cancer, alternative or, more likely, complementary to direct inhibition of the kinase enzymatic domain. This potential therapy to simultaneously inhibit and metabolically "starve" oncogenic kinases may not only lead to higher response rates but also delay, or even prevent, development of drug resistance, frequently seen when kinase inhibitors are used as single agents.

Anaplastic large cell lymphomas with equivocal DUSP22 FISH results: recommendations for clinical reporting and diagnostic evaluation

Anaplastic large cell lymphoma (ALCL), one of the most common T-cell lymphomas, shows unifying pathological features but is clinically and genetically heterogeneous. One genetic subgroup, characterized by recurrent DUSP22 rearrangements (R), has distinct morphologic, immunophenotypic, and molecular features and can be identified in routine pathology practice using a breakapart (BAP) fluorescence in situ hybridization (FISH) probe. However, some cases show equivocal BAP-FISH findings (BAP-FISHEQ) and the features of these cases are poorly understood. Here, we sought to characterize DUSP22 BAP-FISHEQ ALCLs further. First, we applied an immunohistochemistry (IHC) algorithm using TIA1, pSTAT3Y705, and LEF1, which can predict DUSP22-R with high accuracy. Among 37 BAP-FISHEQ ALCLs, 18 (49%) were IHC-algorithm positive (IHCPOS), 8 (21%) were IHC-algorithm negative (IHCNEG), and 11 (30%) were IHCEQ. In 32 BAP-FISHEQ cases, we also applied a dual-color, dual-fusion (D-FISH) probe for t(6;7)(p25.3;q32.3), which accounts for 45% of DUSP22-R ALCLs. Among BAP-FISHEQ cases, D-FISH was positive in 10/18 IHCPOS cases (56%), 0/9 IHCEQ cases (0%), and 0/5 IHCNEG cases (0%). Median survival in BAP-FISHEQ ALCLs was 105 months, intermediate between BAP-FISHPOS ALCLs (median survival not reached) and BAP-FISHNEG ALCLs (19 months). Thus, DUSP22 BAP-FISHEQ ALCLs are clinicopathologically heterogeneous, likely due to an admixture of cases with an unbalanced DUSP22-R and cases with focal deletions without rearrangement. For clinical reporting, we recommend that DUSP22 BAP-FISHEQ ALCLs be reported as equivocal, and not be grouped with BAP-FISHPOS ALCLs. Clinical adoption of an IHC algorithm, possibly supplemented by t(6; 7) D-FISH, could facilitate genetic subtyping in about two-thirds of BAP-FISHEQ ALCLs.

Prognostic factors for primary cutaneous anaplastic large-cell lymphoma: a multicentre retrospective study from Japan

BACKGROUND

The clinical implications of DUSP22 rearrangement and the association between DUSP22 rearrangement and lymphoid enhancer-binding factor 1 (LEF1) expression pattern in CD30+ cutaneous T-cell lymphomas (CTCLs) are unknown.

OBJECTIVES

This study assessed the incidence of DUSP22 rearrangement and its clinical and immunohistochemical implications in primary cutaneous anaplastic large-cell lymphoma (pcALCL), lymphomatoid papulosis (LyP) and CD30+ mycosis fungoides with large-cell transformation (MF-LCT), focusing especially on the association with the prognosis and LEF1 expression pattern. Prognostic factors of pcALCL were also examined.

METHODS

We conducted a multicentre retrospective study including patients with pcALCL, LyP and MF-LCT diagnosed between 1 January 2000 and 31 December 2018 in Japan. Baseline data at diagnosis, treatment course, overall survival (OS) and disease-specific survival (DSS) were collected. Immunohistochemical analysis and fluorescence in situ hybridization to detect DUSP22 and TP63 rearrangement were performed using skin samples at diagnosis. We investigated the association between staining pattern and these gene rearrangements. We also assessed the prognostic implications of clinical status, immunohistochemical results and the presence of gene rearrangements.

RESULTS

DUSP22 rearrangement was detected in 50% (11 of 22) of cases of pcALCL, but not in any cases with LyP (0 of 14) or MF-LCT (0 of 11). TP63 rearrangement was not detected in any case. Clinically, patients with pcALCL with DUSP22 rearrangement did not tend to develop ulcers (P = 0.081). There was no significant association between DUSP22 rearrangement status and immunohistochemical results, including LEF1 expression pattern. T3 stage and the presence of lower limb lesions were significantly associated with shorter OS (P = 0.012 and 0.021, respectively, by log-rank test). Similarly, they were significantly correlated with shorter DSS (P = 0.016 and 0.0001, respectively).

CONCLUSIONS

DUSP22 rearrangement is relatively specific to pcALCL among CD30+ CTCLs in Japan. Although the LEF1 expression pattern was not related to DUSP22 rearrangement in pcALCL, there was no rearrangement if LEF1 was not expressed. We confirmed that T3 stage and the lower limb involvement were significantly associated with decreased OS and DSS. The presence or absence of lower limb lesions should be included in T-stage subcategorization in the future.

Analysis and therapeutic targeting of the IL-1R pathway in anaplastic large cell lymphoma

Anaplastic large cell lymphoma (ALCL), a subgroup of mature T-cell neoplasms with an aggressive clinical course, is characterized by elevated expression of CD30 and anaplastic cytology. To achieve a comprehensive understanding of the molecular characteristics of ALCL pathology and to identify therapeutic vulnerabilities, we applied genome-wide CRISPR library screenings to both anaplastic lymphoma kinase positive (ALK+) and primary cutaneous (pC) ALK- ALCLs and identified an unexpected role of the interleukin-1R (IL-1R) inflammatory pathway in supporting the viability of pC ALK- ALCL. Importantly, this pathway is activated by IL-1α in an autocrine manner, which is essential for the induction and maintenance of protumorigenic inflammatory responses in pC-ALCL cell lines and primary cases. Hyperactivation of the IL-1R pathway is promoted by the A20 loss-of-function mutation in the pC-ALCL lines we analyze and is regulated by the nonproteolytic protein ubiquitination network. Furthermore, the IL-1R pathway promotes JAK-STAT3 signaling activation in ALCLs lacking STAT3 gain-of-function mutation or ALK translocation and enhances the sensitivity of JAK inhibitors in these tumors in vitro and in vivo. Finally, the JAK2/IRAK1 dual inhibitor, pacritinib, exhibited strong activities against pC ALK- ALCL, where the IL-1R pathway is hyperactivated in the cell line and xenograft mouse model. Thus, our studies revealed critical insights into the essential roles of the IL-1R pathway in pC-ALCL and provided opportunities for developing novel therapeutic strategies.

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.

Differential molecular programs of cutaneous anaplastic large cell lymphoma and CD30-positive transformed mycosis fungoides

Background

Discriminating between cutaneous anaplastic large cell lymphoma (cALCL) and CD30-positive transformed mycosis fungoides (CD30+ TMF) is challenging, particularly when they arise in the context of pre-existing mycosis fungoides. The development of molecular diagnostic tools was hampered by the rarity of both diseases and the limited understanding of their pathogenesis.

Methods

In this study, we established a cohort comprising 25 cALCL cases and 25 CD30+ TMF cases, with transcriptomic data obtained from 31 samples. We compared the clinicopathological information and investigated the gene expression profiling between these two entities. Furthermore, we developed an immunohistochemistry (IHC) algorithm to differentiate these two entities clinically.

Results

Our investigation revealed distinct clinicopathological features and unique gene expression programs associated with cALCL and CD30+ TMF. cALCL and CD30+ TMF displayed marked differences in gene expression patterns. Notably, CD30+ TMF demonstrated enrichment of T cell receptor signaling pathways and an exhausted T cell phenotype, accompanied by infiltration of B cells, dendritic cells, and neurons. In contrast, cALCL cells expressed high levels of HLA class II genes, polarized towards a Th17 phenotype, and exhibited neutrophil infiltration. An IHC algorithm with BATF3 and TCF7 staining emerged as potential diagnostic markers for identifying these two entities.

Conclusions

Our findings provide valuable insights into the differential molecular signatures associated with cALCL and CD30+ TMF, which contribute to their distinct clinicopathological behaviors. An appropriate IHC algorithm could be used as a potential diagnostic tool.

MiR-146a-5p enrichment in small-extracellular vesicles of relapsed pediatric ALCL patients promotes macrophages infiltration and differentiation

Anaplastic large cell lymphoma (ALCL) is a CD30-positive lymphoma accounting for 20% of all pediatric T-cell lymphomas. Current first line treatment can cure most of ALCL patients but 10-30% of them are resistant or relapse. In this context, liquid biopsy has the potential to help clinicians in disease screening and treatment response monitoring. Small-RNA-sequencing analysis performed on plasma small-extracellular vesicles (s-EVs) from 20 pediatric anaplastic lymphoma kinase positive (ALK + ) ALCL patients at diagnosis revealed a specific miRNAs cargo in relapsed patients compared to non-relapsed, with seven miRNAs enriched in s-EVs of relapsed patients. MiR-146a-5p and miR-378a-3p showed a negative prognostic impact both in univariate and multivariate analysis, possibly representing, together with let-7 g-5p, a miRNA panel for the early identification of high-risk patients. Among them, miR-146a-5p is known to modulate tumor supporting-M2 macrophages differentiation, but the role of these cells in pediatric ALK + ALCL is still unknown. To elucidate the role of miR-146a-5p and M2 macrophages in pediatric ALCL disease, THP-1-derived macrophages were treated with s-EVs from ALK + ALCL cell lines, showing increased miR-146a-5p intracellular expression, migrating capability and M2-markers CD163 and Arginase-1 upregulation. In turn, conditioned media from M2 macrophages or miR-146a-5p-transfected THP-1 increased ALCL cells' aggressive features and were enriched in interleukin-8. Overall, these data suggest a role of miR-146a-5p in promoting macrophage infiltration and M2-like polarization in ALCL. Our findings incite further investigation on the role of M2 macrophages in ALCL aggressiveness and dissemination, also considering the novel treatment options targeting tumor associated macrophages.

Targeting CCR7-PI3Kγ overcomes resistance to tyrosine kinase inhibitors in ALK-rearranged lymphoma

Anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) show potent efficacy in several ALK-driven tumors, but the development of resistance limits their long-term clinical impact. Although resistance mechanisms have been studied extensively in ALK-driven non-small cell lung cancer, they are poorly understood in ALK-driven anaplastic large cell lymphoma (ALCL). Here, we identify a survival pathway supported by the tumor microenvironment that activates phosphatidylinositol 3-kinase γ (PI3K-γ) signaling through the C-C motif chemokine receptor 7 (CCR7). We found increased PI3K signaling in patients and ALCL cell lines resistant to ALK TKIs. PI3Kγ expression was predictive of a lack of response to ALK TKI in patients with ALCL. Expression of CCR7, PI3Kγ, and PI3Kδ were up-regulated during ALK or STAT3 inhibition or degradation and a constitutively active PI3Kγ isoform cooperated with oncogenic ALK to accelerate lymphomagenesis in mice. In a three-dimensional microfluidic chip, endothelial cells that produce the CCR7 ligands CCL19/CCL21 protected ALCL cells from apoptosis induced by crizotinib. The PI3Kγ/δ inhibitor duvelisib potentiated crizotinib activity against ALCL lines and patient-derived xenografts. Furthermore, genetic deletion of CCR7 blocked the central nervous system dissemination and perivascular growth of ALCL in mice treated with crizotinib. Thus, blockade of PI3Kγ or CCR7 signaling together with ALK TKI treatment reduces primary resistance and the survival of persister lymphoma cells in ALCL.

ALK-negative anaplastic large cell lymphoma with DUSP22 rearrangement has distinctive disease characteristics with better progression-free survival: a LYSA study

ALK-negative anaplastic large cell lymphoma (ALCL) comprises subgroups harboring rearrangements of DUSP22 (DUSP22- R) or TP63 (TP63-R). Two studies reported 90% and 40% 5-year overall survival (OS) rates in 21 and 12 DUSP22-R/TP63- not rearranged (NR) patients, respectively, making the prognostic impact of DUSP22-R unclear. Here, 104 newly diagnosed ALK-negative ALCL patients (including 37 from first-line clinical trials) from the LYSA TENOMIC database were analyzed by break-apart fluorescence in situ hybridization assays for DUSP22-R and TP63-R. There were 47/104 (45%) DUSP22-R and 2/93 (2%) TP63-R cases, including one DUSP22-R/TP63-R case. DUSP22-R tumors more frequently showed CD3 expression (62% vs. 35%, P=0.01), and less commonly a cytotoxic phenotype (27% vs. 82%; P<0.001). At diagnosis, DUSP22- R ALCL patients more frequently had bone involvement (32% vs. 13%, P=0.03). The patient with DUSP22-R/TP63-R ALCL had a rapidly fatal outcome. After a median follow-up of 4.9 years, 5-year progression-free survival (PFS) and OS rates of 84 patients without TP63-R treated with curative-intent anthracycline-based chemotherapy were 41% and 53%, respectively. According to DUSP22 status, 5-year PFS was 57% for 39 DUSP22-R versus 26% for 45 triple-negative (DUSP22-NR/TP63-NR/ALK-negative) patients (P=0.001). The corresponding 5-year OS rates were 65% and 41%, respectively (P=0.07). In multivariate analysis, performance status and DUSP22 status significantly affected PFS, and distinguished four risk groups, with 4-year PFS and OS ranging from 17% to 73% and 21% to 77%, respectively. Performance status but not DUSP22 status influenced OS. The use of brentuximab vedotin in relapsed/refractory patients improved OS independently of DUSP22 status. Our findings support the biological and clinical distinctiveness of DUSP22- R ALK-negative ALCL. Its relevance to outcome in patients receiving frontline brentuximab vedotin remains to be determined.

SBNO2 is a critical mediator of STAT3-driven hematological malignancies

Gain-of-function mutations in the signal transducer and activator of transcription 3 (STAT3) gene are recurrently identified in patients with large granular lymphocytic leukemia (LGLL) and in some cases of natural killer (NK)/T-cell and adult T-cell leukemia/lymphoma. To understand the consequences and molecular mechanisms contributing to disease development and oncogenic transformation, we developed murine hematopoietic stem and progenitor cell models that express mutated STAT3Y640F. These cells show accelerated proliferation and enhanced self-renewal potential. We integrated gene expression analyses and chromatin occupancy profiling of STAT3Y640F-transformed cells with data from patients with T-LGLL. This approach uncovered a conserved set of direct transcriptional targets of STAT3Y640F. Among these, strawberry notch homolog 2 (SBNO2) represents an essential transcriptional target, which was identified by a comparative genome-wide CRISPR/Cas9-based loss-of-function screen. The STAT3-SBNO2 axis is also present in NK-cell leukemia, T-cell non-Hodgkin lymphoma, and NPM-ALK-rearranged T-cell anaplastic large cell lymphoma (T-ALCL), which are driven by STAT3-hyperactivation/mutation. In patients with NPM-ALK+ T-ALCL, high SBNO2 expression correlates with shorter relapse-free and overall survival. Our findings identify SBNO2 as a potential therapeutic intervention site for STAT3-driven hematopoietic malignancies.

A Rare Case of Monomorphic T-Cell Posttransplant Lymphoproliferative Disorder Presenting as Primary Cutaneous Anaplastic Large Cell Lymphoma, ALK Negative

ABSTRACT

Posttransplant lymphoproliferative disorders are a serious complication of hematopoietic and solid organ transplants secondary to iatrogenic immunosuppression. Most cases present as B-cell proliferations which are often Epstein-Barr virus positive; however, ∼10% of cases are T/NK cell and are less commonly associated with Epstein-Barr virus. Of these, cutaneous T/NK-cell lymphomas are exceedingly rare. We report a case of a 69-year-old male, liver transplant recipient who presented with a tender, bright red papule on the left arm during his annual skin cancer screening. Histopathologic evaluation revealed pleomorphic cells with enlarged nuclei, vesicular chromatin, and frequent mitotic figures, intercalating through the dermis. The tumor formed single strands and small cords without epidermal involvement. A patchy mild mixed inflammatory infiltrate was associated with the tumor. Tumor cells were CD2(+), CD4(+), CD30(+), CD3(-), CD20(-), ALK-1(-), and EBER(-). Molecular studies revealed a monoclonal T-cell receptor gamma gene rearrangement by polymerase chain reaction (PCR); ALK gene rearrangement was negative by fluorescence in situ hybridization (FISH). Taken together, the findings were consistent with an ALK-negative anaplastic large cell lymphoma involving skin, which, given the history of liver transplant, qualified as a monomorphic T-cell posttransplant lymphoproliferative disorder. Follow-up imaging studies showed no evidence of systemic disease, supporting an interpretation of primary cutaneous anaplastic large cell lymphoma.

Immunohistochemical Approach to Genetic Subtyping of Anaplastic Large Cell Lymphoma

Anaplastic large cell lymphoma (ALCL) can be classified genetically based on rearrangements (R) of the ALK , TP63 , and/or DUSP22 genes. ALK- R defines a specific entity, ALK-positive ALCL, while DUSP22- R and TP63- R define subgroups of ALK-negative ALCLs with distinct clinicopathologic features. ALK -R and TP63 -R produce oncogenic fusion proteins that can be detected by immunohistochemistry. ALK immunohistochemistry is an excellent surrogate for ALK- R and screening with p63 immunohistochemistry excludes TP63- R in two third of ALCLs. In contrast, DUSP22 -R does not produce a fusion protein and its identification requires fluorescence in situ hybridization. However, DUSP22- R ALCL has a characteristic phenotype including negativity for cytotoxic markers and phospho-STAT3 Y705 . Recently, we also identified overexpression of the LEF1 transcription factor in DUSP22- R ALCL. Here, we sought to validate this finding and examine models for predicting DUSP22- R using immunohistochemistry for LEF1 and TIA1 or phospho-STAT3 Y705 . We evaluated these 3 markers in our original discovery cohort (n=45) and in an independent validation cohort (n=46) of ALCLs. The correlation between DUSP22- R and LEF1 expression replicated strongly in the validation cohort ( P <0.0001). In addition, we identified and validated a strategy using LEF1 and TIA1 immunohistochemistry that predicted DUSP22- R with positive and negative predictive values of 100% after exclusion of indeterminate cases and would eliminate the need for fluorescence in situ hybridization in 65% of ALK-negative ALCLs. This approach had similar results in identifying DUSP22- R in the related condition, lymphomatoid papulosis. Together with previous data, these findings support a 4-marker immunohistochemistry algorithm using ALK, LEF1, TIA1, and p63 for genetic subtyping of ALCL.

PDGFRβ promotes oncogenic progression via STAT3/STAT5 hyperactivation in anaplastic large cell lymphoma

BACKGROUND

Anaplastic large cell lymphoma (ALCL) is an aggressive non-Hodgkin T cell lymphoma commonly driven by NPM-ALK. AP-1 transcription factors, cJUN and JUNb, act as downstream effectors of NPM-ALK and transcriptionally regulate PDGFRβ. Blocking PDGFRβ kinase activity with imatinib effectively reduces tumor burden and prolongs survival, although the downstream molecular mechanisms remain elusive.

METHODS AND RESULTS

In a transgenic mouse model that mimics PDGFRβ-driven human ALCL in vivo, we identify PDGFRβ as a driver of aggressive tumor growth. Mechanistically, PDGFRβ induces the pro-survival factor Bcl-xL and the growth-enhancing cytokine IL-10 via STAT5 activation. CRISPR/Cas9 deletion of both STAT5 gene products, STAT5A and STAT5B, results in the significant impairment of cell viability compared to deletion of STAT5A, STAT5B or STAT3 alone. Moreover, combined blockade of STAT3/5 activity with a selective SH2 domain inhibitor, AC-4-130, effectively obstructs tumor development in vivo.

CONCLUSIONS

We therefore propose PDGFRβ as a novel biomarker and introduce PDGFRβ-STAT3/5 signaling as an important axis in aggressive ALCL. Furthermore, we suggest that inhibition of PDGFRβ or STAT3/5 improve existing therapies for both previously untreated and relapsed/refractory ALK+ ALCL patients.

Clinicopathologic and Genetic Features of Primary T-cell Lymphomas of the Central Nervous System: An Analysis of 11 Cases Using Targeted Gene Sequencing

Primary central nervous system lymphoma (PCNSL) of peripheral T-cell lineage (T-PCNSL) is rare, and its genetic and clinicopathologic features remain unclear. Here, we present 11 cases of T-PCNSL in immunocompetent individuals from a single institute, focusing on their genetic alterations. Seven cases were subject to targeted panel sequencing covering 120 lymphoma-related genes. Nine of the eleven cases were classified as peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), of which one was of γδT-cell lineage. There was one case of anaplastic lymphoma kinase-positive anaplastic large cell lymphoma and another of extranodal natural killer (NK)/T-cell lymphoma (ENKTL) of αβT-cell lineage. The male to female ratio was 7 : 4 and the age ranged from 3 to 75 years (median, 61 y). Most patients presented with neurological deficits (n=10) and showed multifocal lesions (n=9) and deep brain structure involvement (n=9). Tumor cells were mostly small-to-medium, and T-cell monoclonality was detected in all nine evaluated cases. PTCL-NOS was CD4-positive (n=4), CD8-positive (n=3), mixed CD4-positive and CD8-positive (n=1), or CD4/CD8-double-negative (n=1, γδT-cell type). Cytotoxic molecule expression was observed in 4 (67%) of the 6 evaluated cases. Pathogenic alterations were found in 4 patients: one PTCL-NOS case had a frameshift mutation in KMT2C, another PTCL-NOS case harbored a truncating mutation in TET2, and another (γδT-cell-PTCL-NOS) harbored NRAS G12S and JAK3 M511I mutations, and homozygous deletions of CDKN2A and CDKN2B. The ENKTL (αβT-cell lineage) case harbored mutations in genes ARID1B, FAS, TP53, BCOR, KMT2C, POT1, and PRDM1. In conclusion, most of the T-PCNSL were PTCL-NOS, but sporadic cases of other subtypes including γδT-cell lymphoma, anaplastic lymphoma kinase-positive anaplastic large cell lymphoma, and ENKTL were also encountered. Immunophenotypic analysis, clonality test, and targeted gene sequencing along with clinicoradiologic evaluation, may be helpful for establishing the diagnosis of T-PCNSL. Moreover, this study demonstrates genetic alterations with potential diagnostic and therapeutic utility in T-PCNSL.

Coexpression of MCT1 and MCT4 in ALK-positive Anaplastic Large Cell Lymphoma: Diagnostic and Therapeutic Implications

In solid tumors, glycolytic cancer or stromal cells export lactates through monocarboxylate transporter (MCT) 4, while oxidative cancer or stromal cells take up lactates as metabolic fuels or signaling molecules through MCT1. CD147 acts as a chaperone of MCT1 or MCT4. Unlike solid tumors, malignant lymphomas have a peculiar tumor microenvironment. To investigate the metabolic phenotype of malignant lymphoma associated with lactate transport, we analyzed immunohistochemical expressions of MCT1, MCT4, and CD147 in 247 cases of various malignant lymphomas. Surprisingly, both MCT1 and MCT4 were diffusely expressed on tumor cell membranes in all cases (11/11, 100%) of anaplastic lymphoma kinase (ALK) (+) anaplastic large cell lymphoma (ALCL). In contrast, only MCT1 was diffusely expressed in tumor cells of ALK(-) ALCL, as well as in B-cell, natural killer/T-cell, T-cell, and classic Hodgkin lymphomas. In these lymphomas, MCT4 expression was mostly localized to adjacent stromal cells. The pattern of diffuse membranous MCT1 and partial MCT4 expressions in tumor cells was observed in 1 case each of peripheral T-cell lymphoma (1/15, 6.7%) and multiple myeloma (1/34, 2.9%). CD147 was diffusely expressed in all types of lymphoma tumor and/or stromal cells. In conclusion, ALK(+) ALCL has a unique metabolism showing high coexpression of MCT1 and MCT4 in tumor cells. Because only ALK(+) ALCL overexpresses MCT4, immunostaining for MCT4 together with ALK is very useful for differential diagnosis from ALK(-) ALCL or peripheral T-cell lymphoma. Moreover, dual targeting against MCT1 and MCT4 would be an appropriate therapeutic approach for ALK(+) ALCL.

ALK-Negative Anaplastic Large Cell Lymphoma (ALCL): Prognostic Implications of Molecular Subtyping and JAK-STAT Pathway

The anaplastic lymphoma kinase (ALK)-negative anaplastic large cell lymphoma (ALCL) is a clinically distinct but heterogeneous entity and lacks the specific immunophenotypic or genetic features compared with the ALK-positive ALCL. Recent molecular studies have provided genetic landscapes of ALK-negative ALCL that have prognostic significance. In this study, we subtyped ALK-negative ALCL based on DUSP22 rearrangements and TP63 expression and also looked for mutations in JAK-STAT pathway. The subtyping of the ALK-negative ALCL in relation to DUSP22 rearrangement and TP63 expression was done using fluorescence in situ hybridization and immunohistochemistry, respectively. The hotspot JAK-STAT mutations were analyzed using Sanger sequencing and amplification refractory mutation system polymerase chain reaction (PCR) and Signal transducer and activator of transcription 3 (STAT3) expression by immunohistochemistry. Forty-eight cases of ALCL were included with median age of 30 years and sex ratio of 1.8:1. The p63 expression was detected in 26.7% of ALK-negative ALCL cases. DUSP22 rearrangement was noted in 12.5% cases of p63-negative ALK-negative ALCLs. DUSP22 rearranged cases had better overall survival in contrast to p63 expressing and triple negative ALCLs. Triple negative ALCLs showed inferior overall survival rate. STAT3 expression was evident in 61.1% and 60% of ALK-positive and ALK-negative ALCLs, respectively. None of the cases subjected to Sanger sequencing as well as amplification refractory mutation system PCR for hotspot mutation analysis of JAK1 (exon 24) and STAT3 (exon 21) revealed any mutation. ALK-negative ALCL is a genetically heterogeneous disease with widely disparate clinical outcomes. Subtyping of ALK-negative ALCL based on DUSP22 rearrangement and p63 expression provides prognostic information.

Identification and Characterization of Cancer Stem-Like Cells in ALK-Positive Anaplastic Large Cell Lymphoma Using the SORE6 Reporter

Transcription factors Sox2 and Oct4 are essential in maintaining the pluripotency of embryonic stem cells and conferring stemness in cancer stem-like (CSL) cells. SORE6, an in-vitro reporter system, was designed to quantify the transcription activity of Sox2/Oct4 and identify CSL cells in non-hematologic cancers. Using SORE6, we identified and enriched CSL cells in ALK-positive anaplastic large cell lymphoma (ALK + ALCL). Two ALK + ALCL cell lines, SupM2 and UCONN-L2, contained approximately 20% of SORE6+ cells, which were purified based on their expression of green fluorescent protein. We then performed functional studies using single-cell clones derived from SORE6− and SORE6+ cells. Compared to SORE6− cells, SORE6+ cells were significantly more chemoresistant and clonogenic in colony-formation assays. Sox2/Oct4 are directly involved in conferring these CSL properties, since the shRNA knockdown of Sox2 in SORE6+ significantly lowered their chemoresistance, while enforced expression of Sox2/Oct4 in SORE6− cells produced opposite effects. Using Western blots, we found that the expression and subcellular localization of Sox2/Oct4 were similar between SORE6− and SORE6+ cells. However, in SORE6+ but not SORE6− cells, Sox2 and Oct4 abundantly bound to a probe containing the SORE6 consensus sequence. c-Myc, previously shown to regulate cancer stemness in ALK + ALCL, regulated the SORE6 activity. In conclusion, SORE6 is useful in identifying/enriching CSL cells in ALK + ALCL.

Whole Exome Sequencing reveals NOTCH1 mutations in anaplastic large cell lymphoma and points to Notch both as a key pathway and a potential therapeutic target

Patients diagnosed with Anaplastic Large Cell Lymphoma (ALCL) are still treated with toxic multi-agent chemotherapy and as many as 25-50% of patients relapse. To understand disease pathology and to uncover novel targets for therapy, Whole-Exome Sequencing (WES) of Anaplastic Lymphoma Kinase (ALK)+ ALCL was performed as well as Gene-Set Enrichment Analysis. This revealed that the T-cell receptor (TCR) and Notch pathways were the most enriched in mutations. In particular, variant T349P of NOTCH1, which confers a growth advantage to cells in which it is expressed, was detected in 12% of ALK+ and ALK- ALCL patient samples. Furthermore, we demonstrate that NPM-ALK promotes NOTCH1 expression through binding of STAT3 upstream of NOTCH1. Moreover, inhibition of NOTCH1 with γ-secretase inhibitors (GSIs) or silencing by shRNA leads to apoptosis; co-treatment in vitro with the ALK inhibitor Crizotinib led to additive/synergistic anti-tumour activity suggesting this may be an appropriate combination therapy for future use in the circumvention of ALK inhibitor resistance. Indeed, Crizotinib-resistant and sensitive ALCL were equally sensitive to GSIs. In conclusion, we show a variant in the extracellular domain of NOTCH1 that provides a growth advantage to cells and confirm the suitability of the Notch pathway as a second-line druggable target in ALK+ ALCL.

Preclinical Evaluation of Gilteritinib on NPM1-ALK-Driven Anaplastic Large Cell Lymphoma Cells

Anaplastic large cell lymphoma (ALCL) is an aggressive type of non-Hodgkin lymphoma. More than three-fourths of anaplastic lymphoma kinase (ALK)-positive ALCL cases express the nucleophosmin 1 (NPM1)-ALK fusion gene as a result of t(2;5) chromosomal translocation. The homodimerization of NPM1-ALK fusion protein mediates constitutive activation of the chimeric tyrosine kinase activity and downstream signaling pathways responsible for lymphoma cell proliferation and survival. Gilteritinib is a tyrosine kinase inhibitor recently approved by the FDA for the treatment of FMS-like tyrosine kinase mutation-positive acute myeloid leukemia. In this study, we demonstrate for the first time gilteritinib-mediated growth inhibitory effects on NPM1-ALK-driven ALCL cells. We utilized a total of five ALCL model cell lines, including both human and murine. Gilteritinib treatment inhibits NPM1-ALK fusion kinase phosphorylation and downstream signaling, resulting in induced apoptosis. Gilteritinib-mediated apoptosis was associated with caspase 3/9, PARP cleavage, the increased expression of proapoptotic protein BAD, and decreased expression of antiapoptotic proteins, survivin and MCL-1. We also found downregulation of fusion kinase activity resulted in decreased c-Myc protein levels. Furthermore, cell-cycle analysis indicated gilteritinib induced G₀-G₁-phase cell-cycle arrest and reduced CD30 expression. In summary, our preclinical studies explored the novel therapeutic potential of gilteritinib in the treatment of ALCL cells expressing NPM1-ALK and potentially in other ALK or ALK fusion-driven hematologic or solid malignancies. IMPLICATIONS: Our preclinical results explore the use of gilteritinib for the treatment of NPM1-ALK-driven ALCL cells and pave a path for developing future clinical trials. VISUAL OVERVIEW: http://mcr.aacrjournals.org/content/molcanres/19/5/913/F1.large.jpg.

Chromosome 20 loss is characteristic of breast implant-associated anaplastic large cell lymphoma

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a very rare type of T-cell lymphoma that is uniquely caused by a single environmental stimulus. Here, we present a comprehensive genetic analysis of a relatively large series of BIA-ALCL (n = 29), for which genome-wide chromosomal copy number aberrations (CNAs) and mutational profiles for a subset (n = 7) were determined. For comparison, CNAs for anaplastic lymphoma kinase (ALK)- nodal anaplastic large cell lymphomas (ALCLs; n = 24) were obtained. CNAs were detected in 94% of BIA-ALCLs, with losses at chromosome 20q13.13 in 66% of the samples. Loss of 20q13.13 is characteristic of BIA-ALCL compared with other classes of ALCL, such as primary cutaneous ALCL and systemic type ALK+ and ALK- ALCL. Mutational patterns confirm that the interleukin-6-JAK1-STAT3 pathway is deregulated. Although this is commonly observed across various types of T-cell lymphomas, the extent of deregulation is significantly higher in BIA-ALCL, as indicated by phosphorylated STAT3 immunohistochemistry. The characteristic loss of chromosome 20 in BIA-ALCL provides further justification to recognize BIA-ALCL as a separate disease entity. Moreover, CNA analysis may serve as a parameter for future diagnostic assays for women with breast implants to distinguish seroma caused by BIA-ALCL from other causes of seroma accumulation, such as infection or trauma.

Reliable blood cancer cells' telomere length evaluation by qPCR

BACKGROUND

Telomere shortening is linked to a range of different human diseases, hence reliable measurement methods are needed to uncover such associations. Among the plethora of telomere length measurement methods, qPCR is reported as easy to conduct and a cost-effective approach to study samples with low DNA amounts.

METHODS

Cancer cells' telomere length was evaluated by relative and absolute qPCR methods.

RESULTS

Robust and reproducible telomere length measurements were optimized taking into account a careful reference gene selection and by knowing the cancer cells ploidy. qPCR data were compared to "gold standard" measurement from terminal restriction fragment (TRF).

CONCLUSIONS

Our study provides guidance and recommendations for accurate telomere length measurement by qPCR in cancer cells, taking advantage of our expertise in telomere homeostasis investigation in primary cutaneous T-cell lymphomas. Furthermore, our data emphasize the requirement of samples with both, high DNA quality and high tumor cells representation.

Recombinant expression, characterization, and quantification in human cancer cell lines of the Anaplastic Large-Cell Lymphoma-characteristic NPM-ALK fusion protein

Systemic anaplastic large cell lymphoma (ALCL) is an aggressive T-cell lymphoma most commonly seen in children and young adults. The majority of pediatric ALCLs are associated with the t(2;5)(p23;q35) translocation which fuses the Anaplastic Lymphoma Kinase (ALK) gene with the Nucleophosmin (NPM) gene. The NPM-ALK fusion protein is a constitutively-active tyrosine kinase, and plays a major role in tumor pathogenesis. In an effort to advance novel diagnostic approaches and the understanding of the function of this fusion protein in cancer cells, we expressed in E. coli, purified and characterized human NPM-ALK fusion protein to be used as a standard for estimating expression levels in cultured human ALCL cells, a key tool in ALCL pathobiology research. We estimated that NPM-ALK fusion protein is expressed at substantial levels in both Karpas 299 and SU-DHL-1 cells (ca. 4-6 million molecules or 0.5-0.7 pg protein per cell; based on our in-house developed NPM-ALK ELISA; LOD of 40 pM) as compared to the ubiquitous β-actin protein (ca. 64 million molecules or 4.5 pg per lymphocyte). We also compared NPM-ALK/ β-actin ratios determined by ELISA to those independently determined by two-dimensional electrophoresis and showed that the two methods are in good agreement.

A Potent and Selective Small-Molecule Degrader of STAT3 Achieves Complete Tumor Regression In Vivo

Signal transducer and activator of transcription 3 (STAT3) is an attractive cancer therapeutic target. Here we report the discovery of SD-36, a small-molecule degrader of STAT3. SD-36 potently induces the degradation of STAT3 protein in vitro and in vivo and demonstrates high selectivity over other STAT members. Induced degradation of STAT3 results in a strong suppression of its transcription network in leukemia and lymphoma cells. SD-36 inhibits the growth of a subset of acute myeloid leukemia and anaplastic large-cell lymphoma cell lines by inducing cell-cycle arrest and/or apoptosis. SD-36 achieves complete and long-lasting tumor regression in multiple xenograft mouse models at well-tolerated dose schedules. Degradation of STAT3 protein, therefore, is a promising cancer therapeutic strategy.

p53 and β-Catenin Expression Predict Poorer Prognosis in Patients With Anaplastic Large-Cell Lymphoma

BACKGROUND

The Wnt/β-catenin signaling pathway is a major target of p53. β-Catenin/p53 coexpression predicts poorer survival in carcinoma patients. Conversely, CD99 inhibits tumor metastasis through the Wnt/β-catenin pathway. We therefore assessed p53, β-catenin, and CD99 by immunohistochemistry.

PATIENTS AND METHODS

We studied 45 patients with systemic anaplastic large-cell lymphoma (ALCL), including 20 anaplastic lymphoma kinase (ALK)-positive and 25 ALK-negative ALCL. β-Catenin expression was analyzed using phospho-β-catenin-S552 antibody because its nuclear localization indicates Wnt signaling.

RESULTS

In this cohort, p53 expression was associated with ALK-negative ALCL. Furthermore, p53 or β-catenin expression alone or β-catenin/p53 double expression showed poorer overall survival and disease-free survival in patients with ALCL overall and in patients with ALK-negative ALCL. CD99 expression was more frequent in ALK-positive ALCL but had no prognostic significance.

CONCLUSION

This is the first study to evaluate phospho-β-catenin-S552 expression in ALCL. The results of this study, although limited by small patient size, suggest that β-catenin and p53 may play a role in pathogenesis and may be helpful in risk stratification of ALCL patients.

Dependency on the TYK2/STAT1/MCL1 axis in anaplastic large cell lymphoma

TYK2 is a member of the JAK family of tyrosine kinases that is involved in chromosomal translocation-induced fusion proteins found in anaplastic large cell lymphomas (ALCL) that lack rearrangements activating the anaplastic lymphoma kinase (ALK). Here we demonstrate that TYK2 is highly expressed in all cases of human ALCL, and that in a mouse model of NPM-ALK-induced lymphoma, genetic disruption of Tyk2 delays the onset of tumors and prolongs survival of the mice. Lymphomas in this model lacking Tyk2 have reduced STAT1 and STAT3 phosphorylation and reduced expression of Mcl1, a pro-survival member of the BCL2 family. These findings in mice are mirrored in human ALCL cell lines, in which TYK2 is activated by autocrine production of IL-10 and IL-22 and by interaction with specific receptors expressed by the cells. Activated TYK2 leads to STAT1 and STAT3 phosphorylation, activated expression of MCL1 and aberrant ALCL cell survival. Moreover, TYK2 inhibitors are able to induce apoptosis in ALCL cells, regardless of the presence or absence of an ALK-fusion. Thus, TYK2 is a dependency that is required for ALCL cell survival through activation of MCL1 expression. TYK2 represents an attractive drug target due to its essential enzymatic domain, and TYK2-specific inhibitors show promise as novel targeted inhibitors for ALCL.

The Long Non-Coding RNA MIR503HG Enhances Proliferation of Human ALK-Negative Anaplastic Large-Cell Lymphoma

Anaplastic lymphoma kinase (ALK)-negative anaplastic large-cell lymphoma (ALCL) is a rare type of highly malignant, non-Hodgkin lymphoma. Currently, only a few gene rearrangements have been linked to ALK-negative ALCL progression. However, the specific molecular mechanisms underlying the growth of ALK-negative ALCL tumors remain unclear. Here, we investigated aberrantly expressed, long non-coding RNAs (lncRNAs) in ALK-negative ALCL and assessed their potential biological function. MIR503HG (miR-503 host gene) was highly expressed in ALK-negative cell lines and was significantly upregulated in tumors in mice formed from ALK-negative ALCL cell lines. Depletion of MIR503HG suppressed tumor cell proliferation in vivo and in vitro; conversely, its overexpression enhanced tumor cell growth. MIR503HG-induced proliferation was mediated by the induction of microRNA-503 (miR-503) and suppression of Smurf2, resulting in stabilization of the tumor growth factor-β receptor (TGFBR) and enhanced tumor cell growth. Collectively, these findings support a potential role for MIR503HG in cancer cell proliferation through the miR-503/Smurf2/TGFBR axis and indicate that MIR503HG is a potential marker in ALK-negative ALCL.

ALK expression plays different roles in anaplastic large-cell lymphomas and outcome of crizotinib use in relapsed/refractory ALK+ patients in a Chinese population

The prognostic value of anaplastic lymphoma kinase (ALK) expression in patients with anaplastic large-cell lymphoma (ALCL) remains controversial. Data on the clinical features of ALCL in a Chinese population are limited. We retrospectively reviewed 1293 patients with pathologically diagnosed lymphoma at Guangdong General Hospital from June 2007 through August 2016. We evaluated the incidence of ALCL, clinical characteristics, survival status, and outcome of crizotinib use in four relapsed/refractory ALK-positive patients. Among the 1293 patients, 1193 (92.3%) were non-Hodgkin's lymphoma, and 53 (4.4%) of whom were ALCL. Of the 50 ALCL patients, with a median age of 34 years, were evaluated. Among them, 33 (66.0%) were ALK-positive and 17 (34.0%) were ALK-negative. Significantly, more patients younger than 40 years old were ALK-positive than ALK-negative (66.7 vs. 23.5%; P = 0.003). The 5-year progression-free survival (PFS) for ALK-positive and ALK-negative patients were 61 and 11%, and the 5-year overall survival (OS) were 70 and 22%, respectively. Median PFS and OS were significantly better for patients with ALK-positive than ALK-negative (60.1 vs. 9.4 months, P = 0. 017; not reached vs. 32.7 months, P = 0.021). Multivariate analyses identified ALK expression, stage, and bone marrow involvement as independent prognostic factors for PFS and OS. Four relapsed ALK-positive patients were treated with crizotinib and two died. Our results suggest that ALK expression has different prognostic significance in patients with ALCL. Mechanisms underlying early relapse after chemotherapy and resistance to crizotinib need further investigation.

Characteristics And Outcomes Of Anaplastic Large Cell Lymphoma Patients-A Single Centre Experience

BACKGROUND

Anaplastic large cell lymphoma (ALCL) is the second most common T cell lymphoma and 2% of all non-hodgkin lymphoma (NHL). It is an aggressive lymphoma with three subtypes, primary cutaneous ALCL, primary systemic ALK +ve ALCL and primary systemic ALK-ve ALCL depending upon rearrangement of Anaplastic Lymphoma Kinase (ALK) gene into ALK +ve and ALK -ve ALCL. Purpose of study is to determine the outcome of patients with ALCL treated at our institute.

METHODS

In this retrospective analysis, 49 patients with ALCL from 2000 to 2012 were included. Their base line IPI score, stage at presentation, bone marrow involvement, type of chemotherapy, ALK status, extra nodal sites and outcome were recorded.

RESULTS

Median age was 34 years (range 20-72 years), with males' predominance, i.e., 75.5%. At presentation, 7 (14.3%), 12 (24.5%), 14 (28.6%) and 16 (32.7%) were in stage I-IV, respectively. According to IPI risk categorization, there were 27 (55.1%) in low risk, 12 (24.5%) in low intermediate risk, 8 (16.3%) in high intermediate risk and 2 (4%) in high risk. Seventeen patients (34.7%) were ALK +ve while 21 patients (43%) were ALK +ve and 11 patients (22.4%) had unknown status. Kaplan Meir overall survival (OS) at 5 years was 49.9%. Five-year OS in ALK +ve tumour was 67.4% compared to 39.7% in ALK -ve, p=0.05.

CONCLUSIONS

Based on our study results, ALCL is common in males with a trend towards better outcome in Alk+ disease. The majority of patients are in advanced stage of disease at the time of presentation.

Anaplastic large cell lymphoma: pathology, genetics, and clinical aspects

Anaplastic large cell lymphoma (ALCL) was first described in 1985 as a large-cell neoplasm with anaplastic morphology immunostained by the Ki-1 antibody, which recognizes CD30. In 1994, the nucleophosmin (NPM)-anaplastic lymphoma kinase (ALK) fusion receptor tyrosine kinase was identified in a subset of patients, leading to subdivision of this disease into ALK-positive and -negative ALCL in the present World Health Organization classification. Due to variations in morphology and immunophenotype, which may sometimes be atypical for lymphoma, many differential diagnoses should be considered, including solid cancers, lymphomas, and reactive processes. CD30 and ALK are key molecules involved in the pathogenesis, diagnosis, and treatment of ALCL. In addition, signal transducer and activator of transcription 3 (STAT3)-mediated mechanisms are relevant in both types of ALCL, and fusion/mutated receptor tyrosine kinases other than ALK have been reported in ALK-negative ALCL. ALK-positive ALCL has a better prognosis than ALK-negative ALCL or other peripheral T-cell lymphomas. Patients with ALK-positive ALCL are usually treated with anthracycline-based regimens, such as combination cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) or CHOEP (CHOP plus etoposide), which provide a favorable prognosis, except in patients with multiple International Prognostic Index factors. For targeted therapies, an anti-CD30 monoclonal antibody linked to a synthetic antimitotic agent (brentuximab vedotin) and ALK inhibitors (crizotinib, alectinib, and ceritinib) are being used in clinical settings.

T-cell Lymphomas: Updates in Biology and Diagnosis

Nodal-based peripheral T-cell lymphomas are heterogeneous malignancies with overlapping morphology and clinical features. However, the current World Health Organization classification scheme separates these tumors into prognostically relevant categories. Since its publication, efforts to uncover the gene expression profiles and molecular alterations have subdivided these categories further, and distinct subgroups are emerging with specific profiles that reflect the cell of origin for these tumors and their microenvironment. Identification of the perturbed biologic pathways may prove useful in selecting patients for specific therapies and associating biomarkers with survival and relapse.

Therapeutic efficacy of the bromodomain inhibitor OTX015/MK-8628 in ALK-positive anaplastic large cell lymphoma: an alternative modality to overcome resistant phenotypes

Anaplastic large cell lymphomas (ALCL) represent a peripheral T-cell lymphoma subgroup, stratified based on the presence or absence of anaplastic lymphoma kinase (ALK) chimeras. Although ALK-positive ALCLs have a more favorable outcome than ALK-negative ALCL, refractory and/or relapsed forms are common and novel treatments are needed. Here we investigated the therapeutic potential of a novel bromodomain inhibitor, OTX015/MK-8628 in ALK-positive ALCLs.The effects of OTX015 on a panel of ALK+ ALCL cell lines was evaluated in terms of proliferation, cell cycle and downstream signaling, including gene expression profiling analyses. Synergy was tested with combination targeted therapies.Bromodomain inhibition with OTX015 led primarily to ALCL cell cycle arrest in a dose-dependent manner, along with downregulation of MYC and its downstream regulated genes. MYC overexpression did not compensate this OTX015-mediated phenotype. Transcriptomic analysis of OTX015-treated ALCL cells identified a gene signature common to various hematologic malignancies treated with bromodomain inhibitors, notably large cell lymphoma. OTX015-modulated genes included transcription factors (E2F2, NFKBIZ, FOS, JUNB, ID1, HOXA5 and HOXC6), members of multiple signaling pathways (ITK, PRKCH, and MKNK2), and histones (clusters 1-3). Combination of OTX015 with the Bruton's tyrosine kinase (BTK) inhibitor ibrutinib led to cell cycle arrest then cell death, and combination with suboptimal doses of the ALK inhibitor CEP28122 caused cell cycle arrest. When OTX015 was associated with GANT61, a selective GLI1/2 inhibitor, C1156Y-resistant ALK ALCL growth was impaired.These findings support OTX015 clinical trials in refractory ALCL in combination with inhibitors of interleukin-2-inducible kinase or SHH/GLI1.

Reversal of microRNA-150 silencing disadvantages crizotinib-resistant NPM-ALK(+) cell growth

The regulatory microRNA miR-150 is involved in the development of hemopathies and is downregulated in T-lymphomas, such as anaplastic large-cell lymphoma (ALCL) tumors. ALCL is defined by the presence or absence of translocations that activate the anaplastic lymphoma kinase (ALK), with nucleophosmin-ALK (NPM-ALK) fusions being the most common. Here, we compared samples of primary NPM-ALK(+) and NPM-ALK(-) ALCL to investigate the role of miR-150 downstream of NPM-ALK. Methylation of the MIR150 gene was substantially elevated in NPM-ALK(+) biopsies and correlated with reduced miR-150 expression. In NPM-ALK(+) cell lines, DNA hypermethylation-mediated miR-150 repression required ALK-dependent pathways, as ALK inhibition restored miR-150 expression. Moreover, epigenetic silencing of miR-150 was due to the activation of STAT3, a major downstream substrate of NPM-ALK, in cooperation with DNA methyltransferase 1 (DNMT1). Accordingly, miR-150 repression was turned off following treatment with the DNMT inhibitor, decitabine. In murine NPM-ALK(+) xenograft models, miR-150 upregulation induced antineoplastic activity. Treatment of crizotinib-resistant NPM-ALK(+) KARPAS-299-CR06 cells with decitabine or ectopic miR-150 expression reduced viability and growth. Altogether, our results suggest that hypomethylating drugs, alone or in combination with other agents, may benefit ALK(+) patients harboring tumors resistant to crizotinib and other anti-ALK tyrosine kinase inhibitors (TKIs). Moreover, these results support further work on miR-150 in these and other ALK(+) malignancies.

STAT1 is phosphorylated and downregulated by the oncogenic tyrosine kinase NPM-ALK in ALK-positive anaplastic large-cell lymphoma

The tumorigenicity of most cases of ALK-positive anaplastic large-cell lymphoma (ALK+ ALCL) is driven by the oncogenic fusion protein NPM-ALK in a STAT3-dependent manner. Because it has been shown that STAT3 can be inhibited by STAT1 in some experimental models, we hypothesized that the STAT1 signaling pathway is defective in ALK+ ALCL, thereby leaving the STAT3 signaling unchecked. Compared with normal T cells, ALK+ ALCL tumors consistently expressed a low level of STAT1. Inhibition of the ubiquitin-proteasome pathway appreciably increased STAT1 expression in ALK+ ALCL cells. Furthermore, we found evidence that NPM-ALK binds to and phosphorylates STAT1, thereby promoting its proteasomal degradation in a STAT3-dependent manner. If restored, STAT1 is functionally intact in ALK+ ALCL cells, because it effectively upregulated interferon-γ, induced apoptosis/cell-cycle arrest, potentiated the inhibitory effects of doxorubicin, and suppressed tumor growth in vivo. STAT1 interfered with the STAT3 signaling by decreasing STAT3 transcriptional activity/DNA binding and its homodimerization. The importance of the STAT1/STAT3 functional interaction was further highlighted by the observation that short interfering RNA knockdown of STAT1 significantly decreased apoptosis induced by STAT3 inhibition. Thus, STAT1 is a tumor suppressor in ALK+ ALCL. Phosphorylation and downregulation of STAT1 by NPM-ALK represent other mechanisms by which this oncogenic tyrosine kinase promotes tumorigenesis.

Twenty years of modelling NPM-ALK-induced lymphomagenesis

Our current understanding of oncogenic Anaplastic Lymphoma Kinase (ALK)-induced lymphomagenesis has relied for over 20 years on multiple and complementary studies performed on various experimental models, encompassing ALK oncogene expressing cells, their grafts into immune-compromised mice, the generation of genetically engineered mouse models (GEMMs) and, when available, the use of patient samples from Anaplastic Large Cell Lymphoma (ALCL) tumour banks. Of note, and to our knowledge, no ALK-positive ALCL 3D culture system has been described so far. In this review, we will first outline how these different cell and mouse models were designed, and what key findings they revealed (or confirmed) towards oncogenic ALK-induced lymphomagenesis. Secondly, we will discuss how recent and revolutionary advances in genetic engineering technology are likely to complete our understanding of ALK-related disease in an effort to improve current therapeutic approaches.

The role of AP-1 and epigenetics in ALCL

Anaplastic large cell lymphoma (ALCL) is an aggressive, highly proliferative, T-cell lymphoma with increasing incidence worldwide. Anaplastic Lymphoma Kinase (ALK) fusions occur in about 50% of all cases. Most ALK positive cases of ALCL harbor the t(2;5) translocation that leads to expression of Nucleophosmin-Anaplastic Lymphoma Kinase (NPM-ALK). NPM-ALK induces a variety of oncogenic signaling pathways that lead to malignant transformation of T-cells via Activator Protein-1 (AP-1), STAT3 and other (transcription) factors. In addition to the commonly known AP-1 activators Mitogen-Activated Protein Kinases (MAPKs), there are other signaling pathways, such as PI3K/mTOR/AKT, which are implicated in AP-1 activation/expression in ALCL. The AP-1 factor JUNB was shown to drive ALCL proliferation and the expression of the characteristic ALCL Ki-1 antigen, CD30. cJUN and JUNB target PDGFRB, thereby leading to tumor progression and dissemination. Furthermore, aberrant gene expression in ALCL is frequently accompanied by changes in epigenetic regulatory mechanisms, such as DNA methylation patterns. Here, we discuss the role of AP-1 in the pathogenesis of ALCL and provide an overview of pathological epigenetic changes in ALCL cells.

The origins of ALK translocations

Translocations involving the anaplastic lymphoma kinase (ALK) gene locus on chromosome 2p23 were first described in anaplastic large cell lymphoma (ALCL). Although most commonly fused to the nucleophosmin (NPM1) gene on chromosome 5q35, which results in the t(2;5)(p23;q35)/NPM1-ALK translocation, several other ALK translocation partners have meanwhile been identified. Furthermore, apart from ALCL, ALK-involving translocations have been described in other hematopoietic and non-hematopoietic cancers. However, despite a rapid increase in literature on the nature and tissue distribution of ALK-translocations, much less is known about the mechanisms of formation of these translocations. The emergence of translocations has been linked to the transcriptional activity of the respective genome regions, reorganization of the chromatin and activation of the DNA repair machinery. In this review we discuss mechanisms and implications of formation of ALK-translocations.

Convergent mutations and kinase fusions lead to oncogenic STAT3 activation in anaplastic large cell lymphoma

A systematic characterization of the genetic alterations driving ALCLs has not been performed. By integrating massive sequencing strategies, we provide a comprehensive characterization of driver genetic alterations (somatic point mutations, copy number alterations, and gene fusions) in ALK(-) ALCLs. We identified activating mutations of JAK1 and/or STAT3 genes in ∼20% of 88 [corrected] ALK(-) ALCLs and demonstrated that 38% of systemic ALK(-) ALCLs displayed double lesions. Recurrent chimeras combining a transcription factor (NFkB2 or NCOR2) with a tyrosine kinase (ROS1 or TYK2) were also discovered in WT JAK1/STAT3 ALK(-) ALCL. All these aberrations lead to the constitutive activation of the JAK/STAT3 pathway, which was proved oncogenic. Consistently, JAK/STAT3 pathway inhibition impaired cell growth in vitro and in vivo.