Differential expression of BCL-2 family proteins in ALK-positive and ALK-negative anaplastic large cell lymphoma of T/null-cell lineage

Beyond immortality: Epstein-Barr virus and the intricate dance of programmed cell death in cancer development

This comprehensive review delves into the intricate role of programmed cell death in Epstein-Barr virus (EBV)-associated malignancies, focusing on the sophisticated interplay between viral mechanisms and the host's immune response. The central objective is to unravel how EBV exerts control over cell death pathways such as apoptosis, ferroptosis, and autophagy, thereby fostering its persistence and oncogenic potential. By dissecting these mechanisms, the review seeks to identify therapeutic strategies that could disrupt EBV's manipulation of these pathways, enhancing immune recognition and opening new avenues for targeted treatment. A deeper understanding of the molecular underpinnings of EBV's influence on cell death not only enriches the field of viral oncology but also pinpoints targets for drug development. Furthermore, the insights gleaned from this review could catalyze the design of vaccines aimed at preventing EBV infection or curtailing its oncogenic impact. Innovatively, the review synthesizes recent discoveries on the multifaceted roles of non-coding RNAs and cellular signaling pathways in modulating cell death within the context of EBV infection. By consolidating current knowledge and identifying areas where understanding is lacking, it lays the groundwork for future research that could lead to significant advancements in vaccine development and therapeutic interventions for EBV-related cancers. This review underscores the critical necessity for ongoing investigation into the complex interplay between EBV and host cell death mechanisms, with the ultimate goal of enhancing patient outcomes in EBV-associated diseases.

Systemic ALK-negative anaplastic large cell lymphoma: Insights into morphologic, immunophenotypic, genetic and molecular characteristics

Anaplastic large cell lymphoma (ALCL) is a mature T-cell neoplasm characterized by large pleomorphic cells, often with horseshoe- or kidney-shaped nuclei and abundant cytoplasm (hallmark cells), and uniformly strong CD30 expression. Based on ALK expression or ALK rearrangement, ALCL is further classified into ALK-positive (ALK+) and ALK-negative types. This review focuses on the clinicopathologic, immunophenotypic, cytogenetic and molecular features of systemic ALK-negative ALCL. These patients are usually older adults who present with advanced stage disease and often a poor prognosis. ALK-negative ALCL is morphologically indistinguishable from the common pattern of ALK+ ALCL, but some cases show non-common morphology, such as "donut cells", Hodgkin-like features. ALK-negative ALCL is often negative for T-cell antigens (so-called "antigen loss") and in some cases can have a "null" immunophenotype and be confused with other hematopoietic and non-hematopoietic neoplasms. Recurrent genetic/molecular alterations have been identified in systemic ALK-negative ALCL, including rearrangements of DUSP22, TP63, JAK2, FRK, MYC, ROS1 and TYK2; mutations of JAK1, STAT3 and MSCE; and aberrant expression of ERBB4. Some of these alterations may have prognostic significance and/or provide potential therapeutic targets. Data support the idea that ALK-negative ALCL with DUSP22 rearrangement is a distinctive variant due to its unique morphologic, immunophenotypic and molecular features. Gene expression profiling data have shown that ALK-negative ALCL has distinctive molecular signatures, different from ALK+ ALCL and other T-cell lymphomas. Better understanding of the morphologic, immunophenotypic, genetic and molecular features of ALK-negative ALCL will help establish the correct diagnosis, guide therapeutic strategies and improve patient outcomes.

Anaplastic Large Cell Lymphoma With Intraocular or Ocular Adnexal Involvement: A Case Report and Systematic Review

PURPOSE

To review the existing literature on patients with anaplastic large cell lymphoma (ALCL) affecting the globe and/or ocular adnexa, and to present a report documenting the clinical course of a patient with ALCL that involved their globe and ocular adnexa.

METHODS

PubMed, Scopus, and Google scholar were systematically searched for all cases of ALCL involving intraocular or adnexal ocular structures from inception to May 2023. Moreover, a new reported case added to the cases found in searches.

RESULTS

The review identified 1680 studies, with 8 meeting inclusion criteria. A total of 9 patients were included with a mean age of 29.7 years (median: 30.0, range: 1.3-48). Primary ALCL was present in 5/9 (55.6%) patients. The most common ophthalmic manifestations included periorbital swelling (5/8), chemosis (5.8), and decreased vision (5/7). Misdiagnoses were initially made in 3 patients, and the lag time to correct diagnosis from 3 weeks to 3 months. CD30 expression was positive in all cases, and 6/9 patients were positive for anaplastic lymphoma kinase, resulting in 6/9 patients being diagnosed with anaplastic lymphoma kinase-positive ALCL. In terms of management modalities, chemotherapy was administered in 8/9 patients, while radiation therapy was utilized in 4/9 patients, and 2 underwent autologous stem cell transplantation. Five (55.6%) patients succumbed to ALCL while 4 (44.4%) were alive and disease-free at the last follow-up. The median times from the initial presentation of ALCL to death, ophthalmic presentation to death, and diagnosis to death were 4.12 months (range: 1.1-168.0), 2.62 months (range: 1.1-144), and 4.00 months (range: 0.10-168), respectively. The median follow-up duration was 21.0 months (range: 1.1-168.0).

CONCLUSIONS

ALCL involving the globe and ocular adnexa is a rare and highly malignant tumor that can mimic benign clinical conditions. Early biopsy and aggressive treatment with chemotherapy regimens such as CHOP and radiation therapy may be useful.

ALK+ Anaplastic Large Cell Lymphoma (ALCL)-Derived Exosomes Carry ALK Signaling Proteins and Interact with Tumor Microenvironment

Simple Summary

ALK+ anaplastic large cell lymphoma (ALK+ ALCL) is a distinct type of aggressive non-Hodgkin lymphoma of T-cell origin, which is characterized by overexpression and activation of ALK kinase due to chromosomal translocations of the gene. The most frequent chromosomal aberration is the t(2;5) resulting in the NPM-ALK chimeric protein, which exerts its oncogenic functions through activation of multiple oncogenic pathways. Exosomes, the best characterized type of extracellular vesicles, are secreted from the tumor cells, thus transferring signals to other cells that uptake exosomes. In this study, we demonstrate that ALK+ ALCL cells secrete exosomes that carry critical molecules of ALK signaling, which can be taken up by other cells with significant biologic effects including functional interactions with tumor microenvironment cells, which may contribute to tumor aggressiveness and possibly resistance to treatment.

Abstract

The oncogenic pathways activated by the NPM-ALK chimeric kinase of ALK+ anaplastic large cell lymphoma (ALCL) are well characterized; however, the potential interactions of ALK signaling with the microenvironment are not yet known. Here we report that ALK+ ALCL-derived exosomes contain critical components of ALK signaling as well as CD30, and that exosome uptake by lymphoid cells led to increased proliferation and expression of critical antiapoptotic proteins by the recipient cells. The bone marrow fibroblasts highly uptake ALK+ ALCL-derived exosomes and acquire a cancer-associated fibroblast (CAF) phenotype. Moreover, exosome-mediated activation of stromal cells altered the cytokine profile of the microenvironment. These interactions may contribute to tumor aggressiveness and possibly resistance to treatment.

B-cell lymphoma-2 (BCL2) downregulation is a useful feature -supporting a neoplastic phenotype in mature T-cell lymphomas

Normal T-cells express high levels of BCL2 protein, data regarding BCL2 expression status and its diagnostic utility in T-cell lymphoma is scarce. We evaluated BCL2 expression in a series of mature T-cell lymphoproliferations including indolent and more recently recognized entities (follicular helper T-cell (TFH) lymphomas). Sixty-six neoplastic biopsies (60 patients) representing mature nodal, extranodal and leukemia T-cell neoplasms were collected from three institutes (2 US and 1 Japan) and were compared with reactive T-cells in 8 benign tissues/blood and 9 T-cell rich B-cell proliferations. BCL2 immunostaining was performed and scored based on intensity weighted H-score (0-300). Next generation sequencing (5 cases), BCL2 gene sequencing, and real time-PCR (3 cases) were conducted. Association of H-score with overall survival (using proportional hazards modeling) was assessed in non-leukemic T-cell lymphoproliferations (TCL). Most TCLs showed significantly downregulated median BCL2 H-score (125, range 18-300) with the exception of T-cell prolymphocytic leukemia (T-PLL) and hepatosplenic T-cell lymphoma (HSTL) both of which showed uniform strong retention of BCL2 as did the 8 reactive tissues (median H-score 280; p=0.000). Notably all TFH lymphoma CD4 neoplastic T-cells, subcutaneous panniculitis-like T-cell lymphoma (SPTCL) CD8 adipocyte-rimming T-cells and T-cell large lymphocyte leukemia (T-LGLL) with pathogenic STAT5B and TP53 mutation showed BCL2 downregulation. No BCL2 mutations were observed by NGS or sequencing with decreased BCL2 mRNA transcripts by real-time PCR. BCL2 downregulation is pervasive among many T-cell lymphoproliferations and unrelated to any mutations. There is utility for BCL2 immunostaining in some challenging situations as discussed in manuscript.

Clinicopathological features of syncytial variant nodular sclerosis Hodgkin lymphoma

The syncytial variant of nodular sclerosis Hodgkin lymphoma (SV-NSHL) is uncommon, and its clinicopathological features have not been well analyzed. In this study, we collected 142 cases of SV-NSHL. There were 76 (53.5%) males and 66 (46.5%) females with a median age of 28 years (range, 12-78); 59.9% were younger than 30 years. Patients usually presented with a mediastinal mass (97.6%) and often with bulky (35.7%) and advanced stage disease (3 or 4) (39.7%). Follow-up showed that 61.1% of patients developed relapse after standard therapy. Morphologically, the neoplasms were composed of sheets or large clusters of pleomorphic neoplastic cells with a cohesive appearance that were frequently associated with necrosis. Neutrophils and eosinophils were frequent in the background, whereas small lymphocytes were decreased. Immunohistochemical analysis showed that the following markers were frequently positive: CD30 (100%), MUM1/IRF4 (96%), PAX5 (95%), PD-L1 (91%), and CD15 (80%). CD45 was negative in all cases. Epstein-Barr virus-encoded small RNA (EBER) was detected in 19% of cases. In this cohort, age above 30 years (P = .0430), presence of B-type symptoms (P = .0394), elevated serum lactate dehydrogenase level (P = .0004), and disease relapse (P = .0108) were associated with a poorer overall survival. In contrast, patients with EBER-positive neoplasms had a better survival (P = .0418). Compared with a control group of non-SV-NSHL patients, patients with SV-NSHL were associated with a poorer overall survival (P = .011). These data suggest that SV morphology is associated with a poorer prognosis in patients treated with traditional standard-of-care therapy for classic Hodgkin lymphoma.

The Dual Role of Autophagy in Crizotinib-Treated ALK+ ALCL: From the Lymphoma Cells Drug Resistance to Their Demise

Autophagy has been described as harboring a dual role in cancer development and therapy. Depending on the context, it can exert either pro-survival or pro-death functions. Here, we review what is known about autophagy in crizotinib-treated ALK⁺ ALCL. We first present our main findings on the role and regulation of autophagy in these cells. Then, we provide literature-driven hypotheses that could explain mechanistically the pro-survival properties of autophagy in crizotinib-treated bulk and stem-like ALK⁺ ALCL cells. Finally, we discuss how the potentiation of autophagy, which occurs with combined therapies (ALK and BCL2 or ALK and RAF1 co-inhibition), could convert it from a survival mechanism to a pro-death process.

Anaplastic Lymphoma Kinase- and CD30-Positive Anaplastic Large-Cell Lymphoma of the External Auditory Canal

Anaplastic large-cell lymphoma (ALCL), a form of non-Hodgkin’s lymphoma, is rare in the external auditory canal (EAC). ALCL in the EAC region is challenging for clinicians and pathologists. We report a 34-year-old male presented with the chief complaint of a painless mass in the left EAC for approximately 2 weeks. Anaplastic lymphoma kinase (ALK)- and CD30-positive ALCL were confirmed using computed tomography, positron emission tomography, histopathological examination and IHC staining. We compared the clinicopathological characteristics of our patient with those of previous cases. The biopsy and IHC findings confirmed the rare diagnosis of ALK- and CD30-positive ALCL of the EAC. Radiotherapy and concurrent chemoradiotherapy are indicated for lymphoma depending on the extent of the disease. Brentuximab vedotin as initial salvage therapy should be considered for recurrent or refractory ALK-positive ALCL.

PD-L1 expression is associated with ALK positivity and STAT3 activation, but not outcome in patients with systemic anaplastic large cell lymphoma

The programmed cell death 1 (PD-1) pathway is a recently recognized mechanism of tumor immune evasion. In this study, programmed cell death ligand 1 (PD-L1) expression was evaluated in 95 patients with systemic anaplastic large cell lymphoma: 45 ALK+ and 50 ALK-. ALK+ anaplastic large cell lymphoma was more often positive for PD-L1 than ALK- anaplastic large cell lymphoma (76% vs 42%, p = 0.002). ALK- anaplastic large cell lymphoma showed a strong correlation between PD-L1 expression and STAT3 activation (measured by pSTAT3^Tyr705) (r = 0.8, p < 0.0001). In contrast, the PD-L1/pSTAT3 correlation was weaker in ALK+ anaplastic large cell lymphoma (r = 0.4, p = 0.08). In ALK- anaplastic large cell lymphoma, the PD-L1+ subgroup was more often EMA positive (69% vs 20%, p = 0.02) and tended to be less often CD2+ (50% vs 83%, p = 0.059). In ALK+ anaplastic large cell lymphoma, PD-L1 was not associated with pathologic features (all p > 0.05). Negative ALK status and high IPI score (≥3) were associated with shorter overall survival (p = 0.009 and p = 0.0005, respectively). Overall survival was not different between patients with PD-L1+ vs PD-L1- anaplastic large cell lymphoma (p = 0.44), regardless of ALK status and International Prognostic Index (IPI) score. We conclude that PD-L1 expression is more common in ALK+ anaplastic large cell lymphoma than ALK- anaplastic large cell lymphoma. In ALK- anaplastic large cell lymphoma, PD-L1 is strongly correlated with STAT3 activation and is associated with more frequent EMA and less frequent CD2 expression. PD-L1 has no prognostic significance in predicting the outcome of patients with systemic anaplastic large cell lymphoma, regardless of ALK status. PD-L1 expression on the anaplastic large cell lymphoma cells suggests these patients as potential candidates for PD-1 blockade immunotherapy.

CD8 expression in anaplastic large cell lymphoma correlates with noncommon morphologic variants and T-cell antigen expression suggesting biological differences with CD8-negative anaplastic large cell lymphoma

Anaplastic large cell lymphoma (ALCL) is a T-cell neoplasm characterized by uniformly strong CD30 expression and common absence of T-cell markers. Most ALCL cases express CD4, but a small subset of ALCL cases has been reported to express CD8. Little is known about the clinicopathologic and prognostic features of CD8+ ALCL. In this study, CD8 was assessed in 158 patients with systemic ALCL: CD8 was positive in 13 of 67 (19%) ALK+ and 13 of 91 (14%) ALK-negative neoplasms. In ALK+ ALCL, the CD8+ subgroup more often showed a noncommon morphologic pattern (69% vs 13%, P = .0001) and was more often positive for CD2 (100% vs 45%, P = .001), CD3 (92% vs 24%, P = .0001), and CD7 (100% vs. 39%, P = .002), but less frequently positive for CD25 (50% vs. 100%, P = .02). Patients with ALK+ ALCL and CD8+ neoplasms also had a higher relapse rate (82% vs 48%, P = .05) and more often underwent stem cell transplant (73% vs 36%, P = .04). CD8 expression did not correlate with patient overall survival or progression-free survival regardless of ALK status (all P > 0.05). We conclude that CD8+ ALCL cases appear to be biologically different from the more common CD8-negative ALCL cases. Our data suggest that CD8 positivity in ALK+ ALCL helps to identify a subset of patients more prone to relapse or more in need of stem cell transplant during their clinical course, although there was no impact on survival in this cohort.

ALCL by any other name: the many facets of anaplastic large cell lymphoma

Anaplastic large cell lymphomas (ALCLs) encompass a group of CD30(+) non-Hodgkin T-cell lymphomas. While the different subtypes of ALCLs may share overlapping clinical patient demographics as well as histological and immunohistochemical phenotypes, these tumours can drastically differ in clinical behaviour and genetic profiles. Currently, four distinct ALCL entities are recognised in the 2016 WHO classification: anaplastic lymphoma kinase (ALK)(+), ALK(-), primary cutaneous and breast implant-associated. ALK(+) ALCL demonstrates a spectrum of cell cytology ranging from small to large lymphoma cells and characteristic 'hallmark' cells. ALK(+) ALCL consistently demonstrates ALK gene rearrangements and carries a favourable prognosis. ALK(-) ALCL morphologically and immunohistochemically mimics ALK(+) ALCL but lacks the ALK gene rearrangement. ALK(-) ALCLs are associated with variable prognoses depending on specific gene rearrangements; while DUSP22-rearranged cases have favourable outcomes similar to ALK(+) ALCLs, cases with p63 rearrangements carry a dismal prognosis and 'triple-negative' cases (those lacking ALK, DUSP22 and TP63 rearrangements) have an intermediate prognosis. Primary cutaneous ALCL presents as a skin lesion, lacks the ALK gene translocation and carries a favourable prognosis, similar or superior to ALK(+) ALCL. Breast implant-associated ALCL presents as a seroma with a median of 8-10 years after implant placement, lacks the ALK gene translocation and has an overall favourable but variable prognosis, depending on extent of disease at diagnosis and treatment. In this review, we present the clinical, pathological and genetic features of the ALCLs with emphasis on practical points and differential diagnoses for practising pathologists.

Methotrexate significantly induces apoptosis by inhibiting STAT3 activation in NPM-ALK-positive ALCL cells

Anaplastic large cell lymphoma (ALCL) is associated with a characteristic chromosomal translocation that generates the oncogenic fusion protein, nucleophosmin-anaplastic lymphoma kinase (NPM-ALK). Methotrexate is a commonly used chemotherapeutic drug in the treatment of multiple cancers due to its inhibition of dihydrofolate reductase (DHFR), which suppresses the synthesis of DNA. In the present study, we found that low-dose methotrexate significantly induced apoptosis in transformed Ba/F3 cells expressing NPM-ALK by inhibiting the activation of signal transducer and activator of transcription factor 3 (STAT3), a critical downstream molecule of NPM-ALK. Although methotrexate prevented the phosphorylation of STAT3, it did not affect the activity of NPM-ALK. A co-treatment with folinic acid prevented the methotrexate-induced inhibition of STAT3 activation and induction of apoptosis, suggesting that methotrexate exerts its cytotoxic effects by depleting tetrahydrofolate (THF) in transformed cells by NPM-ALK. Furthermore, methotrexate induced the down-regulation of the anti-apoptotic protein, MCL-1, DNA damage, and the activation of a p53 tumor suppressor, leading to apoptosis through the inhibition of STAT3. Methotrexate significantly induced apoptosis in ALK inhibitor-resistant cells expressing the NPM-ALK mutant harboring the point mutation, G262R, and in ALCL patient-derived NPM-ALK-positive Ki-JK cells. Collectively, these results demonstrate the potential therapeutic application of methotrexate, which inhibits the activation of STAT3, to NPM-ALK-positive ALCL.

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.

Blockade of crizotinib-induced BCL2 elevation in ALK-positive anaplastic large cell lymphoma triggers autophagy associated with cell death

Anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphomas are tumors that carry translocations involving the ALK gene at the 2p23 locus, leading to the expression of ALK tyrosine kinase fusion oncoproteins. Amongst hematologic malignancies, these lymphomas are particular in that they express very low levels of B-cell lymphoma 2 (BCL2), a recognized inhibitor of apoptosis and autophagy, two processes that share complex interconnections. We have previously shown that treatment of ALK-positive anaplastic large cell lymphoma cells with the ALK tyrosine kinase inhibitor crizotinib induces autophagy as a pro-survival response. Here, we observed that crizotinib-mediated inactivation of ALK caused an increase in BCL2 levels that restrained the cytotoxic effects of the drug. BCL2 downregulation in combination with crizotinib treatment potentiated loss of cell viability through both an increase in autophagic flux and cell death, including apoptosis. More importantly, our data revealed that the blockade of autophagic flux completely reversed impaired cell viability, which demonstrates that excessive autophagy is associated with cell death. We propose that the downregulation of BCL2 protein, which plays a central role in the autophagic and apoptotic machinery, combined with crizotinib treatment may represent a promising therapeutic alternative to current ALK-positive anaplastic large cell lymphoma treatments.

Expression of granzyme B sensitizes ALK+ ALCL tumour cells to apoptosis-inducing drugs

Background

The serine protease Granzyme B (GzB) is primarily expressed by cytotoxic T lymphocytes and natural killer cells, and functions in allowing these cells to induce apoptosis in virally-infected or transformed cells. Cancers of both lymphoid and non-lymphoid origin also express GzB, and in some cases this expression has been linked to pathogenesis or sensitizing tumour cells to cell death. For example, GzB expression in urothelial carcinoma was implicated in promoting tumour cell invasion, whereas its expression in nasal-type NK/T lymphomas was found to correlate with increased apoptosis. GzB expression is also a hallmark of the non-Hodgkin lymphoma, anaplastic lymphoma kinase-positive, anaplastic large cell lymphoma (ALK+ ALCL). Given the fact that ALK+ ALCL exhibits high levels of apoptosis and is typically responsive to conventional chemotherapy, we examined whether GzB expression might play a role in sensitizing ALK+ ALCL tumour cells to apoptosis.

Methods

ALK+ ALCL cell lines stably expressing GzB or non-targeting (control) shRNA were generated and apoptosis was examined by anti-PARP western blotting and terminal deoxynucleotidyl transferase dUTP nick end labelling. Both spontaneous apoptosis and apoptosis in response to treatment with staurosporine or doxorubicin were investigated. In order to assess whether additional granzymes might be important in promoting cell death in ALK+ ALCL, we examined whether other human granzymes were expressed in ALK+ ALCL cell lines using reverse-transcriptase PCR and western blotting.

Results

Expression of several GzB shRNAs in multiple ALK+ ALCL cell lines resulted in a significant decrease in GzB levels and activity. While spontaneous apoptosis was similar in ALK+ ALCL cell lines expressing either GzB or control shRNA, GzB shRNA-expressing cells were less sensitive to staurosporine or doxorubicin-induced apoptosis as evidenced by reduced PARP cleavage and decreased DNA fragmentation. Furthermore, we found that GzB is the only granzyme that is expressed at significant levels in ALK+ ALCL cell lines.

Conclusions

Our findings are the first to demonstrate that GzB expression sensitizes ALK+ ALCL cell lines to drug-induced apoptosis. This suggests that GzB expression may be a factor contributing to the favourable response of this lymphoma to treatment.

Crizotinib (PF-2341066) induces apoptosis due to downregulation of pSTAT3 and BCL-2 family proteins in NPM-ALK(+) anaplastic large cell lymphoma

Nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) is an aberrant fusion gene product with tyrosine kinase activity and is expressed in substantial subset of anaplastic large cell lymphomas (ALCL). It has been shown that NPM-ALK binds to and activates signal transducer and activator of transcription 3 (STAT3). Although NPM-ALK(+) ALCL overall shows a better prognosis, there is a sub-group of patients who relapses and is resistant to conventional chemotherapeutic regimens. NPM-ALK is a potential target for small molecule kinase inhibitors. Crizotinib (PF-2341066) is a small, orally bioavailable molecule that inhibits growth of tumors with ALK activity as shown in a subgroup of non-small lung cancer patients with EML4-ALK expression. In this study, we have investigated the in vitro effects of Crizotinib in ALCL cell line with NPM-ALK fusion. Crizotinib induced marked downregulation of STAT3 phosphorylation, which was associated with significant apoptotic cell death. Apoptosis induction was attributed to caspase-3 cleavage and marked downregulation of the Bcl-2 family of proteins including MCL-1. These findings implicate that Crizotinib has excellent potential to treat patients with NPM-ALK(+) ALCL through induction of apoptotic cell death and downregulation of major oncogenic proteins in this aggressive lymphoma.

Primary cutaneous CD30-positive anaplastic large-cell lymphoma of the external auditory canal

Primary cutaneous T-cell lymphoma is rare. Cutaneous lymphoma is defined as primary when there is an absence of nodal or systemic disease during the first 6 months following diagnosis. We report what we believe to be the first documented case of a primary cutaneous CD30-positive anaplastic large-cell lymphoma of the external auditory canal. The patient was an elderly woman who presented with progressively worsening right otalgia and hypoacusis. Otoscopy revealed an erythematic, ulcerative, nonbleeding, localized lesion in the anterosuperior area of the external auditory canal. The patient underwent an excisional biopsy, and after the diagnosis was established, she underwent 22 sessions of radiotherapy. During follow-up, she exhibited no evidence of recurrence.

(18)F-FDG PET in Patients with Primary Systemic Anaplastic Large Cell Lymphoma: Differential Features According to Expression of Anaplastic Lymphoma Kinase

PURPOSE

Primary systemic anaplastic large cell lymphoma (ALCL) is divided into two entities according to the expression of anaplastic lymphoma kinase (ALK). We investigated (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) findings in primary systemic ALCL according to ALK expression.

METHODS

Thirty-seven patients who had baseline PET before CHOP (cyclophosphamide, doxorubicin, vincristine and prednisolone)-based chemotherapy were enrolled. Among them, patients who underwent interim and/or post-therapy PET were further investigated for the treatment response and survival analysis. Baseline PET was analyzed visually and semi-quantitatively using peakSUV, and interim and post-therapy PETs were visually analyzed.

RESULTS

All cases were (18)F-FDG-avid on baseline PET. The peakSUV of ALK-positive ALCL (n = 16, 18.7 ± 10.5) was higher than that of ALK-negative ALCL (n = 21, 10.0 ± 4.9) (P = 0.006). In ALK-negative ALCL, complete response (CR) rate in negative-interim PET was higher than positive-interim PET (100 % vs 37.5 %, P = 0.02); however, there was no such difference in ALK-positive ALCL (100 % vs 75 %, P = 0.19). The 3-year progression-free survival (PFS) was not significantly different between ALK-positive and ALK-negative ALCL (72.7 % vs 47.6 %, P = 0.34). In ALK-negative ALCL, negative interim and post-therapy PET patients had better 3-year PFS than positive interim (83.3 % vs 25.0 %, P = 0.06) and post-therapy PET patients (70.0 % vs 20.0 %, P = 0.04). In contrast, ALK-positive ALCL had no such differences between PFS and PET results.

CONCLUSIONS

On baseline PET, all cases showed (18)F-FDG-avidity, and ALK expression was related to higher (18)F-FDG uptake. ALK-positive patients tend to have better PFS than ALK-negative patients. Negative-interim PET was a good indicator of CR, and interim or post-therapy PET was helpful for predicting the prognosis only in the ALK-negative group.

Anaplastic large cell lymphoma, ALK-negative

Anaplastic large cell lymphoma (ALCL), anaplastic lymphoma kinase (ALK)-negative (ALCL-ALK-) is a provisional entity in the WHO 2008 Classification that represents 2-3% of NHL and 12% of T-cell NHL. No particular risk factor has been clearly identified for ALCL, but a recent study showed an odds ratio of 18 for ALCL associated with breast implants. Usually, the architecture of involved organs is eroded by solid, cohesive sheets of neoplastic cells, with peripheral T-cell lymphoma-not otherwise specified (PTCL-NOS) and classical Hodgkin lymphoma being the main differential diagnoses. In this regard, staining for PAX5 and CD30 is useful. Translocations involving ALK are absent, TCR genes are clonally rearranged. CGH and GEP studies suggest a tendency of ALCL-ALK- to differ both from PTCL-NOS and from ALCL-ALK+. Patients with ALCL-ALK- are usually adults with a median age of 54-61 years, and a male-to-female ratio of 0.9. At presentation, ALCL-ALK- is often in III-IV stage, with B symptoms, high International Prognostic Index score, high lactate dehydrogenase serum levels, and an aggressive course. ALCL-ALK- presents with lymph node involvement in ∼50% of cases; extranodal spread (20%) is less common. Staging work-up for ALCL-ALK- is similar to that routinely used for nodal NHL. Overall prognosis is poor, with a 5-year OS of 30-49%, which is significantly worse when compared to OS reported in patients with ALCL-ALK+ (5-year: 70-86%). Patients with systemic ALCL exhibit a significantly better survival compared with patients with PTCL-NOS, with a 5-year OS of 51% and 32%, respectively. Age, PIT scoring system, β2-microglobulin, and bone marrow infiltration are the main prognostic factors. The expression of proteins involved in the regulation of apoptosis (caspase 3, Bcl-2, PI9) and of CD56 is related to clinical outcome. ALCL-ALK- is generally responsive to doxorubicin-containing chemotherapy, but relapses are frequent. CHOP is the most commonly used regimen to treat systemic ALCL with complete remission rates of 56%, and a 10-year DFS of 28%. Encouraging results have been reported with more intensive chemotherapy regimens. The addition of etoposide improved outcome. Alemtuxumab-CHOP regimen was associated with excellent remission rate but increased toxicity. The role of high-dose chemotherapy supported by ASCT has not been investigated in a trial of exclusively ALCL patients. When used in first remission, it was associated with a 5-year PFS of 64%. High-dose chemotherapy with ASCT is the standard therapeutic option for patients with relapsed or refractory disease. The role of allogeneic transplantation in patients with relapsed/refractory ALCL remains to be defined but there are data to support the contention that a graft-versus-lymphoma effect does exist. Myeloablative conditioning has been associated with 5-year PFS and OS of 40% and 41%, respectively, but a 5-year TRM of 33% was reported. Allo-SCT can be an option for relapsed/refractory ALCL in younger patients, preferably in the setting of a clinical trial. Pralatrexate, anti-CD30 monoclonal antibodies, brentuximab vedotin (SGN-35) in particular, (131)I-anti-CD45 radioantibody, yttrium-anti-CD25 radioimmunoconjugates, histone deacetylase inhibitors, bortezomib, gemcitabine, vorinostat, lenalidomide, and their combinations represent the most appealing chemotherapy and/or targeted agents to be investigated in future trials.

Clinical and laboratory characteristics of systemic anaplastic large cell lymphoma in Chinese patients

Background

Systemic anaplastic large cell lymphoma (S-ALCL) is a rare disease with a highly variable prognosis and no standard chemotherapy regimen. Anaplastic lymphoma kinase (ALK) has been reported as an important prognostic factor correlated with S-ALCL in many but not all studies. In our study, we retrospectively analyzed 92 patients with S-ALCL from the Peking University Lymphoma Center for clinical and molecular prognostic factors to make clear the role of ALK and other prognostic factors in Han Chinese S-ALCL.

Results

The majority of Chinese S-ALCL patients were young male patients (median age 26, male/female ratio 1.7) and the median age was younger than previous reports regardless of ALK expression status. The only statistically significant different clinical characteristic in S-ALCL between ALK positive (ALK⁺) and ALK negative (ALK^-) was age, with a younger median age of 22 for ALK⁺ compared with 30 for ALK^-. However, when pediatric patients (≤18) were excluded, there was no age difference between ALK⁺ and ALK^-. The groups did not differ in the proportion of males, those with clinical stage III/IV (49 vs 51%) or those with extranodal disease (53 vs 59%). Of 73 evaluable patients, the 3-year and 5-year survival rates were 60% and 47%, respectively. Univariate analysis showed that three factors: advanced stage III/IV, lack of expression of ALK, and high Ki-67 expression, were associated with treatment failure in patients with S-ALCL. However, ALK expression correlated with improved survival only in patients younger than 14 years, while not in adult patients. In multivariate analysis, only clinical stage was an independent prognostic factor for survival. Expressions of Wilms tumor 1 (WT1) and B-cell lymphoma 2 protein (BCL-2) correlated with the expression of ALK, but they did not have prognostic significance. High Ki-67 expression was also a poor prognostic factor.

Conclusions

Our results show that ALK expression alone is not sufficient to determine the outcome of ALCL and other prognostic factors must be considered. Clinical stage is an independent prognostic factor. Ki-67 expression is a promising prognostic factor.

An algorithmic approach to the diagnosis of NK and T cell lymphomas

Lymphomas of natural killer (NK) and T cell lineages are uncommon disorders, although as a group they are more usually encountered in Asia compared to Western populations. In part due to their rarity, diagnosis and classification of T cell lymphomas often pose a challenge to clinicians and pathologists. Although there are morphological features that are characteristic of certain subtypes, correct classification of NK and T cell neoplasms relies heavily on the immunophenotype. With few exceptions, non-random genetic alterations such as translocations are less often seen in T cell neoplasms, adding to the diagnostic difficulty. Given these limitations, pathological diagnosis and classification of NK and T cell lymphomas are anything but straightforward. This paper attempts to present a practical algorithmic approach for the general pathologist who is confronted with these neoplasms.

CCL11-CCR3 interactions promote survival of anaplastic large cell lymphoma cells via ERK1/2 activation

CCR3 is a specific marker of anaplastic large cell lymphoma (ALCL) cells. ALCL cells also express CCL11, a ligand for CCR3, leading to the hypothesis that CCL11 may play an autocrine role in ALCL progression. In this study, we investigated a role of CCL11 in cell survival and growth of human Ki-JK cells, established from an ALCL patient, and murine EL-4 lymphoma cells. Both Ki-JK and EL-4 cells expressed cell surface CCR3. CCL11 increased cell survival rates of Ki-JK cells in a dose-dependent manner, whereas it promoted EL-4 cell proliferation. Furthermore, CCL11 induced phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 in both Ki-JK cells and EL-4 cells. Cell survival and tumor proliferation promoted by CCL11 was completely blocked by inhibition of ERK phosphorylation. CCL11 induced expression of antiapoptotic proteins, Bcl-xL and survivin, in Ki-JK cells. CCL11 also enhanced tumor growth of EL-4 and Ki-JK cells in vivo. Consistent with these results, tumor cells of cutaneous ALCL expressed CCR3 and increased levels of phosphorylated ERK1/2, Bcl-xL, and survivin in situ. Thus, our findings prompt a novel therapeutic approach to treat relapses of an aggressive form of lymphoma based on the discovery that a cell surface marker of disease functions as a critical autocrine growth receptor.

A successfully treated inflammatory myofibroblastic tumor of the mandible with long-term follow-up and review of the literature

Inflammatory myofibroblastic tumor (IMT) of the oral cavity is an extremely rare clinical and pathological disease entity. It was originally described in the lung but has recently been reported in various anatomic sites. We report such a case of inflammatory myofibroblastic tumor of the mandible in a 14-year-old girl. The patient presented with an aggressive ulcerative soft tissue mass of 3 months duration in the mandibular molar gingiva. Histologically, the lesion was composed of fibroblastic or myofibroblastic spindle cell proliferations with infiltrative margins in an inflammatory background. Immunohistochemically, the fibroblastic or myofibroblastic spindle cells were positive for vimentin, α-smooth muscle actin, and Ki-67 (MIB-1) but negative for desmin, pan-cytokeratin, S-100 protein, CD34, CD68, CD99, bcl-2, β-catenin, estrogen receptor, progesterone receptor, ALK-1, and p53. These spindle cells were focally and weakly Ki-67- (MIB-1-) positive. The MIB-1 labeling index was 5%. The results of in situ hybridization for Epstein-Barr virus-encoded-RNA were negative. The ratio of IgG4+/IgG+ plasma cells was about 10%. A pathological diagnosis of inflammatory myofibroblastic tumor was made. The postoperative course was uneventful, and the patient has had no recurrence in the 10-year follow-up period. Although no evidence of oral inflammatory myofibroblastic tumor recurrence or malignant transformation has been reported, it has been observed that in inflammatory myofibroblastic tumors of other regions, a prolonged follow-up is necessary after surgical resection. No other case of an IMT patient under 20 years of age has appeared in either the English or the Japanese literature.

Anaplastic large cell lymphoma: another entity in the differential diagnosis of small round blue cell tumors

We saw in consultation a biopsy specimen from a 6-year old girl with anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL). The tumor arose in soft tissue of the neck, and diagnostic tissue was obtained by core needle biopsy. Histologically, the neoplasm was cellular without pattern. Immunohistochemical workup with a large panel of antibodies at another institution showed immunoreactivity for NB84 and neuron specific enolase (dim). Antibodies specific for CD3, CD20, and CD45/LCA were negative; CD30 or ALK were not assessed. Electron microscopy showed cytoplasmic structures thought to be neurosecretory granules. The neoplasm was interpreted initially as a neuroblastoma. At the time of our review, we considered the possibility of ALCL. Immunohistochemical analysis for CD30 showed bright, uniform expression and ALK was positive in a nuclear and cytoplasmic pattern, confirming the diagnosis of ALK+ ALCL. The purpose of this review is to discuss ALK+ ALCL and many of the other entities included under the rubric of small round blue cell tumor, with a focus on tumors that occur in children.

The therapeutic potential of p53 reactivation by nutlin-3a in ALK+ anaplastic large cell lymphoma with wild-type or mutated p53

p53 is expressed frequently, but is rarely mutated in anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) tumours. Nutlin-3a is a recently developed small molecule that targets Mdm2, a critical negative regulator of p53, and disrupts the p53-Mdm2 interaction resulting in p53 stabilization and activation. We show that nutlin-3a activates p53 in ALK+ ALCL cells carrying a wild type (wt) or mutated but partially functional p53 gene resulting in p53-dependent cell-cycle arrest and apoptosis. Cell-cycle arrest was associated with upregulation of the cyclin-dependent kinase inhibitor p21. Nutlin-3a-induced apoptotic cell death was accompanied by Bax and Puma upregulation, downregulation of Bcl-xl, survivin, and caspase-3 cleavage, and this was reduced when p53-dependent transactivation activity was inhibited by pifithrin-alpha, or when pifithrin-mu was used to inhibit direct p53 targeting of mitochondria. Nutlin-3a sensitized the activation of the extrinsic apoptotic pathway in wt-p53 ALK+ ALCL cells, in part, through upregulation of DR-5 and downregulation of c-Flip(S/L), and was synergistic with TRAIL in cell death induction. In addition, nutlin-3a treatment enhanced doxorubicin cytotoxicity against ALK+ ALCL cells harbouring mt p53, and this was associated with p73 upregulation. These data suggest that disruption of the p53-mdm2 interaction by nutlin-3a offers a novel therapeutic approach for ALK+ ALCL patients.

Expression of ALK protein, mRNA and fusion transcripts in anaplastic large cell lymphoma

Systemic anaplastic large cell lymphoma (ALCL) can be divided into two subgroups, anaplastic lymphoma kinase (ALK)-positive and ALK-negative, based on the expression of ALK protein. Expression of this protein is due to genetic alterations of ALK at 2p23. Overall, observations on ALK protein, ALK mRNA, ALK-associated genetic alterations and their relationships, to one another are not often reported in the literature. In this study, we investigated the expression of ALK protein, mRNA and fusion transcripts involving ALK and their relationships in ALCL and analyzed formalin-fixed, paraffin-embedded tissues. Forty-five human cases were analyzed with immunohistochemistry for the ALK protein and RT-PCR for ALK mRNA and seven kinds of ALK involved fusion transcripts. Our results showed that the expression of ALK protein, ALK mRNA and ALK fusion transcripts were significantly related to one another (P<0.01). Consistent with the expression of ALK protein, patients presenting with ALK mRNA or ALK involved fusion transcripts were significantly younger than those lacking ALK gene alteration (P<0.01). This study demonstrates expression of both ALK protein and ALK mRNA are positively correlated with expression of ALK-associated fusion transcripts. Combined detection of ALK protein, ALK mRNA and ALK fusion transcripts can complement each other to aid in the diagnosis of ALCL.

Hyperactivated STAT3 in ALK-positive diffuse large B-cell lymphoma with clathrin-ALK fusion

Anaplastic lymphoma kinase (ALK)-positive large B-cell lymphoma is a rare subtype of diffuse large B-cell lymphoma (DLBCL). Although a few cases of ALK-positive large B-cell lymphoma harbor nucleophosmin-ALK chromosomal translocation similar to ALK-positive anaplastic large cell lymphoma, most reported cases are characterized by t(2;17)(p23;q23) involving the clathrin gene. Here, we report 2 cases of ALK-positive DLBCL. The 2 cases presented similar morphologic features and immunohistochemical characteristics, that is, positivity for ALK, IgA, CD138, and MUM1; weak positivity for CD30 and CD79a; and negativity for CD20. The clathrin-ALK transcript was identified by reverse transcription-polymerase chain reaction, and the sequence was determined by direct sequencing. Recently, the essential role of STAT3 activation as well as STAT 5 activation in nucleophosmin-ALK fusion protein-mediated lymphomagenesis was reported. However, differential effects of ALK-fusion variant proteins on proliferation, transformation, and invasion properties were reported. Thus, we evaluated the phosphorylation status of STAT 3 and STAT 5, and found highly hyperphosphorylated STAT 3 on tyrosine 705 but not STAT 5 in our 2 cases of ALK-positive DLBCL with clathrin-ALK fusion. Furthermore, STAT 5A expression was not detected in either of the ALK-positive DLBCL cases, although 11 of the 36 ALK-negative DLBCL cases revealed STAT 5A expression. Expression of the antiapoptotic proteins survivin and BCL-X(L), which were believed to be the targets of STAT 3, was investigated. However, there were no significant associations between expression of survivin or BCL-X(L) and ALK positivity among the diffuse large B-cell lymphomas. In summary, similar signaling transduction mechanism involving STAT proteins seems to underlie DLBCL harboring the clathrin-ALK or nucleophosmin-ALK fusion gene.

Pathobiology of ALK+ anaplastic large-cell lymphoma

Anaplastic large-cell lymphoma (ALCL) was initially recognized on the basis of morphologic features and the consistent expression of CD30. It then became evident that the majority of these tumors are derived from lymphoid cells of T or null immunophenotype. The subsequent finding that t(2;5)(p23;q35) occurs in 40% to 60% of ALCL patients established a distinct clinicopathologic entity. This chromosomal translocation induces the formation of the chimeric protein nucleophosmin-anaplastic lymphoma kinase (NPM-ALK), which possesses significant oncogenic potential resulting from the constitutive activation of the tyrosine kinase ALK. In addition to its specific pathophysiologic events, NPM-ALK-expressing lymphoma presents with consistent clinical manifestations. Only 13 years after the identification of NPM-ALK, tremendous progress has been made in our understanding of this molecule because of the relentless efforts of multiple investigators who have dissected its biologic roles using in vitro and in vivo experimental models. Several upstream modulators, cross-reacting oncogenes, and downstream effectors of NPM-ALK have been identified and characterized. Understanding these interacting oncogenic systems is expected to facilitate the design of new therapeutic strategies and agents. In this review, we briefly discuss ALCL and focus on NPM-ALK.

Inflammatory myofibroblastic tumor: comparison of clinicopathologic, histologic, and immunohistochemical features including ALK expression in atypical and aggressive cases

Inflammatory myofibroblastic tumor (IMT) is a neoplasm of intermediate biologic potential. In this study, we report a subset of IMTs with histologic atypia and/or clinical aggressiveness that were analyzed for clinicopathologic features, outcome, and immunohistochemical expression of anaplastic lymphoma kinase (ALK) and other markers to identify potential pathologic prognostic features. Fifty-nine IMTs with classic morphology (5 cases), atypical histologic features (21 cases), local recurrence (27 cases), and/or metastasis (6 cases) were studied. Immunohistochemistry was performed for ALK1 and other markers (Mib-1, c-Myc, cyclin D1, caspase 3, Bcl-2, Mcl-1, survivin, p27, CD56, p53, MDM-2) using standard techniques. The 59 IMTs had an age at diagnosis ranging from 3 weeks to 74 years (mean 13.2 y, median 11 y, 44% in the first decade). The mean tumor size was 7.8 cm. Sites included the abdomen or pelvis in 64%, lung in 22%, head and neck in 8%, and extremities in 5%. The follow-up ranged from 3 months to 11 years, with a mean of 3.6 years and a median of 3 years. Thirty-three patients had local recurrences, including 13 with multiple local recurrences and 6 patients with both local recurrences and distant metastases. Six patients died of disease, 5 with local recurrences, and 1 with distant metastases. Histologic evolution to a more pleomorphic cellular, spindled, polygonal, or round cell morphologic pattern was observed in 7 cases. Abdominal and pelvic IMTs had a recurrence rate of 85%. Recurrent and metastatic IMTs were larger, with mean diameters of 8.7 and 11 cm, respectively. Cytoplasmic ALK reactivity was seen in 56%. ALK-negative IMTs occurred in older patients (mean age 20.1) years and had greater nuclear pleomorphism, atypia, and atypical mitoses. All 6 metastatic IMTs were ALK-negative. Nuclear expression of p53 was detected in 80% of IMTs overall, but in only 25% of the metastatic subset. There were no significant differences among the subgroups for c-Myc, cyclin D1, MDM-2, Mcl-1, Bcl-2, CD56, p27, caspase 3, or survivin expression. In conclusion, among these 59 IMTs, ALK reactivity was associated with local recurrence, but not distant metastasis, which was confined to ALK-negative lesions. Absent ALK expression was associated with a higher age overall, subtle histologic differences, and death from disease or distant metastases (in a younger subset). Other proliferative, apoptotic, and prognostic markers did not correlate well with morphology or outcome. Thus, ALK reactivity may be a favorable prognostic indicator in IMT and abdominopelvic IMTs recur more frequently.

Differences in survivin location and Bcl-2 expression in CD30+ lymphoproliferative disorders of the skin compared with systemic anaplastic large cell lymphomas: an immunohistochemical study

BACKGROUND

Cutaneous CD30+ lymphoproliferative disorders (LPDs) are a spectrum of disease associated with a favourable prognosis. Systemic anaplastic large cell lymphoma (ALCL), although morphologically and phenotypically similar, differs in clinical presentation and has a less favourable biological behaviour. Dysregulation of apoptosis, the process regulating cell population by programmed death, can explain the differences among these disorders.

OBJECTIVES

We investigated the expression of two inhibitors of apoptosis, survivin and Bcl-2 protein, in serial skin lesion samples from CD30+ LPDs compared with systemic ALCL.

METHODS

Immunohistochemical analysis with antibodies against anaplastic lymphoma kinase (ALK)-1 protein, survivin and Bcl-2 protein was performed in 10 cutaneous CD30+ LPDs (five lymphomatoid papulosis, five ALCL) and 18 systemic ALCLs. Reverse transcription-polymerase chain reaction studies for ALK and ALK/nucleophosmin were also performed.

RESULTS

Cutaneous CD30+ LPDs shared a heterogeneous expression of cytoplasmic survivin with all systemic ALCLs, and of Bcl-2 with systemic ALK- ALCLs; however, they differ from systemic ALK- ALCLs because they lack nuclear survivin (P = 0.045), and from systemic ALK+ ALCLs by a higher expression of Bcl-2 (P = 0.045) and a lack of ALK-1. Overall, coexpression of Bcl-2 and nuclear survivin in CD30+ LPDs was associated with a less favourable disease survival.

CONCLUSIONS

The different patterns of expression of Bcl-2 and survivin in CD30+ LPDs might have an impact on their different biological and clinical behaviour. Moreover, nuclear localization of survivin, similarly to ALK, may be a useful marker for predicting a systemic form of ALCL with cutaneous presentation.

NPM-ALK oncogenic kinase promotes cell-cycle progression through activation of JNK/cJun signaling in anaplastic large-cell lymphoma

Anaplastic large-cell lymphoma (ALCL) frequently carries the t(2;5)(p23;q35), resulting in aberrant expression of nucleophosmin-anaplastic lymphoma kinase (NPM-ALK). We show that in 293T and Jurkat cells, forced expression of active NPM-ALK, but not kinase-dead mutant NPM-ALK (210K>R), induced JNK and cJun phosphorylation, and this was linked to a dramatic increase in AP-1 transcriptional activity. Conversely, inhibition of ALK activity in NPM-ALK(+) ALCL cells resulted in a concentration-dependent dephosphorylation of JNK and cJun and decreased AP-1 DNA-binding. In addition, JNK physically binds NPM-ALK and is highly activated in cultured and primary NPM-ALK(+) ALCL cells. cJun phosphorylation in NPM-ALK(+) ALCL cells is mediated by JNKs, as shown by selective knocking down of JNK1 and JNK2 genes using siRNA. Inhibition of JNK activity using SP600125 decreased cJun phosphorylation and AP-1 transcriptional activity and this was associated with decreased cell proliferation and G2/M cell-cycle arrest in a dose-dependent manner. Silencing of the cJun gene by siRNA led to a decreased S-phase cell-cycle fraction associated with upregulation of p21 and downregulation of cyclin D3 and cyclin A. Taken together, these findings reveal a novel function of NPM-ALK, phosphorylation and activation of JNK and cJun, which may contribute to uncontrolled cell-cycle progression and oncogenesis.

Role of ancillary techniques in diagnosing and subclassifying non-Hodgkin's lymphomas on fine needle aspiration cytology

Non-Hodgkin's lymphomas (NHL) are tumours of the lymphoid cells. During the process of development of lymphoid cells, neoplasia may evolve at any point. Neoplastic cells usually carry the imprint of cell of origin at the stage of origin. Various types of NHL may have similar morphology with wide variation in origin, immunophenotype and other biological features. Different ancillary laboratory techniques may help to overcome the limitations of morphology in this aspect. The commonly used ancillary techniques in lymphomas are immunocytochemistry (IC), flow cytometry, Southern blot (SB) technique, polymerase chain reaction (PCR) and fluorescent in situ hybridization (FISH). In addition, laser scanning cytometry (LSC) and DNA microarray technologies are in the research phase. Various laboratory techniques are used for immunophenotyping, demonstration of monoclonality, identification of chromosomal translocation, assessment of cell kinetics and expression of mRNA in the tumour cells. Flow cytometry helps in rapid immunophenotying of NHL and it has an added advantage over IC in recognizing the co-expression of CD markers. Fine needle aspiration cytology (FNAC) combined with flow immunophenotyping may help us to diagnose and subclassify certain NHLs, such as follicular lymphoma and mantle cell lymphoma, which were previously recognized as pure morphological entities. Loss of morphology is one of the important limitations of flow cytometry. LSC can overcome this limitation by studying morphology along with the immunophenotyping pattern of individual cells. Chromosomal changes in NHL can be identified by SB, PCR and FISH. Molecular diagnosis of NHL helps in diagnosis, subclassification, prognostic assessment and even in planning of therapy. DNA microarray is a relatively newer and promising technology. It gives information about the expression of several thousands of genes in a tumour in a single experiment. In the near future, FNAC combined with ancillary techniques may play a major role in diagnosis, subclassification and management of lymphomas.

Intrinsic apoptotic pathway in anaplastic large cell lymphoma

Anaplastic large cell lymphoma (ALCL) includes a subset of tumors that has abnormalities of chromosome 2p23, resulting in overexpression of anaplastic lymphoma kinase (ALK). Previous studies have reported differences in apoptotic rate and expression levels of apoptosis regulatory proteins between ALK+ and ALK- ALCL. In this study, we assessed for expression of the intrinsic apoptotic pathway proteins cytochrome c, apoptosis protease-activating factor 1, and procaspase 9 in 2 ALK+ ALCL cell lines and 42 ALCL tumors (17 ALK+, 25 ALK-). We used the Karpas 299 and SU-DHL-1 cell lines, and the inhibitors Z-LEHD-FMK (specific for caspase 9) and Boc-D-FMK (general caspase inhibitor) to investigate the role of caspase 9 activation in chemotherapy-induced apoptotic cell death. Caspase 9 activity was significantly increased in Karpas-299 and SU-DHL-1 cells after chemotherapy treatment, but remained as low as control levels with addition of either caspase inhibitor. Both caspase inhibitors rescued a substantial fraction of Karpas 299 and SU-DHL-1 cells from drug-induced cell death. In ALCL tumors, expression of cytochrome c, apoptosis protease-activating factor 1, and procaspase 9 was also assessed and correlated with apoptotic rate and activated caspase 3 levels. Cytochrome c was expressed in all 13 (100%) ALK+ and 18 (95%) of 19 ALK- ALCL tumors. Apoptosis protease-activating factor 1 was detected in 14 (88%) of 16 ALK+ and 19 (79%) of 24 ALK- ALCL tumors. Procaspase 9 was expressed in 5 (30%) of 17 ALK+ and 2 (8%) of 25 ALK- ALCL tumors (P = .09). In the entire study group (ALK+ and ALK- ALCL), procaspase 9 expression levels significantly correlated with apoptotic rate (P = .02) and activated caspase 3 levels (P = .05). This correlation could not be shown in the ALK+ or ALK- ALCL subgroups, presumably because of the small sample size. In conclusion, chemotherapy-induced cell death in ALK+ ALCL cells involves the intrinsic apoptotic pathway, and apoptosome function may be an important determinant of apoptosis in ALCL tumors.

Oral inflammatory myofibroblastic tumor demonstrating ALK, p53, MDM2, CDK4, pRb, and Ki-67 immunoreactivity in an elderly patient

Inflammatory myofibroblastic tumor (IMT) is a controversial lesion composed of myofibroblasts, accompanied by varying numbers of inflammatory cells. Various pathogenetic factors have been proposed (ie, reactive, infectious, autoimmune, and neoplastic) but the etiology of most IMTs remains unknown. Here we review the literature of oral IMTs, detailing the demographic profile of these rare lesions. Moreover, we present an unusual case of IMT arising from the mandibular alveolar mucosa of an 82-year-old female. Microscopic examination revealed plump spindle cells set in a myxoid vascular stroma admixed with inflammatory cells. Numerous large ganglion cell-like cells were seen, some exhibiting emperipolesis of neutrophils. Ultrastructurally, prominent myofibroblasts with abundant rough endoplasmic reticulum were noted. Tumor cells were immunoreactive for vimentin, smooth muscle actin, and KP1 (CD68), and negative for desmin, S-100, and EBV-LMP. The lesion was excised without margins and the patient has manifested no evidence of disease at an 18-month recall. In an attempt to further delineate the potential neoplastic nature of this lesion, we assessed the immunohistochemical expression of various markers that have been linked to neoplastic transformation. The recorded positivity for ALK, p53, MDM2, CDK4, pRb, and Ki-67, despite the absence of bcl-2 reactivity, strongly favors the neoplastic origin of the studied tumor.

Reappraisal of BCL3 as a Molecular Marker of Anaplastic Large Cell Lymphoma

The BCL3 gene was initially discovered through its involvement in a recurring translocation, t(14;19)(q32;q13), which is found in some patients with B-cell chronic lymphocytic leukemia (B-CLL). The translocation leads to the juxtaposition of BCL3 to the immunoglobulin heavy chain gene locus, resulting in high-level expression of the BCL3 transcript. The Bcl-3 protein includes 7 tandem copies of the ankyrin repeat element in the central domain, a structure that is characteristic of the IkappaB family of inhibitors of the nuclear factor kappaB transcription factors. Anaplastic large cell lymphoma (ALCL) is a subtype of aggressive non-Hodgkin's lymphoma that is characterized by expression of CD30 and the NPM/ALK chimeric protein, which is generated by t(2;5)(p23;q35). We compared the gene expression profiles of ALCL with those of another CD30+ neoplasm, Hodgkin's disease (HD), and found that BCL3 is expressed at higher levels in ALCL than in HD. A comparison by real-time polymerase chain reaction assay revealed that t(2;5)+ ALCL expresses a high level of BCL3 messenger RNA relative to the levels expressed in other hematologic tumors, and the level in ALCL is comparable to or even higher than that in t(14;19)+ B-CLL. An immunohistochemical analysis of ALCL tumor tissues showed that the lymphoma cells exhibited strong nuclear staining by a monoclonal antibody against Bcl-3. We suggest that Bcl-3 sequestrates the (p50)2 homodimer to the nucleus and that the kappaB sites are occupied by the (p50)2/Bcl-3 ternary complex. Future studies should identify the relationships among the 3 independent molecules (ie, NPM/ALK, CD30, and Bcl-3) that are activated in t(2;5)+ ALCL.

Immunoreactivity of CD99 in non-Hodgkin's lymphoma: unexpected frequent expression in ALK-positive anaplastic large cell lymphoma

To verify the spectrum of CD99-expressing lymphoid malignancy, an immunohistochemical study for CD99 was carried out in 182 cases of non-Hodgkin's lymphoma, including 21 lymphoblastic lymphomas, 11 small lymphocytic lymphomas, 9 mantle cell lymphomas, 12 follicular lymphomas, 37 diffuse large B cell lymphomas, 18 Burkitt's lymphomas, 28 NK/T-cell lymphomas, 8 angioimmunoblastic T-cell lymphomas, 23 peripheral T-cell lymphomas, unspecified, and 15 systemic anaplastic large cell lymphomas. CD99 was positive in all T-lymphoblastic lymphomas and in 60% of B-lymphoblastic lymphomas. Majority of T and NK cell lymphomas were negative for CD99, except anaplastic large cell lymphomas (ALCLs). Eight of 15 cases (54%) of ALCLs reacted with anti CD99 antibody. Seven of 10 (70%) ALK positive ALCLs expressed CD99, whereas only 1 of 5 (20%) ALK negative ALCLs were positive. Of the mature B-cell lymphomas, 5.4% (2/37) of diffuse large B cell lymphomas and 11.1% (2/18) of Burkitt's lymphomas expressed CD99. In conclusion, CD99 is infrequently expressed in mature B and T cell lymphomas, except ALK-positive ALCL. High expression of CD99 in ALK-positive ALCL is unexpected finding and its biologic and clinical significances have yet to be clarified.

Activation status of the JAK/STAT3 pathway in mantle cell lymphoma

CONTEXT

Signal transducer and activator of transcription 3 (STAT3) is oncogenic, and we previously found evidence of constitutive STAT3 activation in a relatively small number of frozen mantle cell lymphoma (MCL) cell tumors.

OBJECTIVES

To comprehensively survey the activation and phosphorylation status of STAT3 in MCL and to assess if STAT3 activation in these tumors is due to cytokine stimulation by examining the phosphorylation and activation status of Janus kinase (JAK), the physiologic activator of STAT3.

DESIGN

We evaluated 43 formalin-fixed, paraffin-embedded MCL tumors using immunohistochemistry and phospho-specific antibodies against STAT3 and JAK.

RESULTS

There were 37 small cell and 6 blastoid cases. There was heterogeneous expression of phospho-STAT3 (pSTAT3), with 23 negative cases (53%), 12 weakly positive cases (28%), and 8 strongly positive cases (19%). JAK3 was the only member detectable in 3 MCL cell lines, and immunoprecipitation data showed a relatively low level of tyrosine phosphorylation of JAK3 in these cells. Using immunohistochemistry, phospho-JAK3 (pJAK3) was detectable in 18 (44%) of 41 MCL tumors examined, and pJAK3 expression correlated with that of pSTAT3 (P = .008). A notable exception to this correlation was seen in the blastoid variant, since 4 (67%) of 6 blastoid cases were pSTAT3 positive but pJAK3 negative.

CONCLUSIONS

We have confirmed our previous finding that STAT3 is constitutively activated in MCL tumors, with an overall frequency of 47% in this series. STAT3 activation in the small cell but not the blastoid variant of MCL is likely mediated by JAK3.

JunB expression is a common feature of CD30+ lymphomas and lymphomatoid papulosis

JunB is a member of the Jun family of proteins that are components of the AP-1 transcription factor complex. AP-1 is involved in cell proliferation and apoptosis. Recent evidence suggests that Hodgkin and Reed-Sternberg cells overexpress JunB and that JunB facilitates constitutive CD30 expression by binding to an AP-1 site in the CD30 promoter. In this study we surveyed JunB expression in a variety of CD30+ lymphoma types including 42 cases of anaplastic large cell lymphoma, 36 classical Hodgkin lymphoma, 15 cutaneous anaplastic large cell lymphoma, and 11 CD30+ diffuse large B-cell lymphoma. In addition, seven cases of nodular lymphocyte-predominant Hodgkin lymphoma and 42 diffuse large B-cell lymphoma, known to be CD30-, were analyzed. JunB expression was assessed using tissue microarrays, immunohistochemistry and a monoclonal antibody specific for JunB. Expression of JunB was observed in 41 of 42 cases of anaplastic large cell lymphoma, including all 21 cases positive for anaplastic lymphoma kinase and 20 of 21 (95%) negative for anaplastic lymphoma kinase. JunB was also expressed in all cases of classical Hodgkin lymphoma, cutaneous anaplastic large cell lymphoma and CD30+ diffuse large B-cell lymphoma, and in lymphomatoid papulosis. By contrast, all nodular lymphocyte-predominant Hodgkin lymphomas and diffuse large B-cell lymphomas that were CD30- were also JunB-. We conclude that JunB is expressed in virtually all CD30+ lymphomas and is a potential target for experimental therapy in patients with these tumors.

Leukotriene B4 receptor inhibitor LY293111 induces cell cycle arrest and apoptosis in human anaplastic large-cell lymphoma cells via JNK phosphorylation

Anaplastic large-cell lymphoma (ALCL) is a heterogeneous lymphoma category in which a subset of cases carry the t(2;5)(p23;q35) or variant translocations resulting in overexpression of anaplastic lymphoma kinase (ALK). LY293111 (2-[2-propyl-3-[3-[2-ethyl-4-(4-fluorophenyl)-5-hydroxyphenoxy]-propoxy]-phenoxy] benzoic acid sodium salt) is a leukotriene B4 receptor antagonist, which was found to be safe and tolerable in Phase I clinical trials. In this study, we investigated the potential therapeutic effects and mechanisms of action of LY293111 in ALCL cell lines. LY293111 inhibited proliferation of both ALK(+) and ALK(-) ALCL cell in a dose-dependent fashion and induced complete G(1)-S cell cycle arrest, which was accompanied by upregulation of p27 and downregulation of cyclin E. Pretreatment with LY293111 for 4 h resulted in profound inhibition of serum-induced phosphorylation of extracellular-regulated kinases-1 and 2 and Akt and a concomitant increase in the phosphorylation of the stress-activated kinase c-jun N-terminal kinases (JNK). Simultaneously, LY293111 induced caspase-dependent apoptosis via activation of the intrinsic pathway, including early loss of mitochondrial inner transmembrane potential and the production of reactive oxygen species (ROS), cleavage of caspases-9, -3, poly ADP-ribose polymerase (PARP) and X-linked inhibitor of apoptosis. The phospho-JNK inhibitor SP600125 partially protected Sup-M2 cells from LY293111-induced apoptosis, PARP cleavage and ROS generation, suggesting a role for JNK in LY293111-induced cell death. These results warrant further studies of LY293111 in ALCL.

Differential expression of cyclin D3 in ALK+ and ALK− anaplastic large cell lymphoma

As defined in the World Health Organization classification, anaplastic large cell lymphoma (ALCL) is a distinct type of non-Hodgkin lymphoma of T/null cell lineage, a subset of which is associated with translocations involving 2p23 resulting in expression of anaplastic lymphoma kinase (ALK). The most common translocation, the t(2;5)(p23;q35), results in expression of nucleophosmin (NPM)-ALK. NPM-ALK has been shown to activate signal transducer and activator of transcription (STAT) 3, a transcriptional regulator of cyclin D3. In this study, we assessed cyclin D3 expression in 2 ALK+ ALCL cell lines (Karpas 299 and SU-DHL1) and 1 ALK- ALCL cell line (Mac2A) by Western blot analysis. We also assessed cyclin D3 expression in 52 ALCL tumors (32 ALK+, 20 ALK-) by immunohistochemistry using tissue microarrays. These results were compared with phosphorylated (activated) STAT3 (pSTAT3) expression. Both ALK+ ALCL cell lines, but not the ALK- ALCL cell line, expressed cyclin D3 and pSTAT3. Cyclin D3 was expressed in 25 (78%) of 32 ALK+ ALCL tumors and in 4 (20%) of 20 ALK- ALCL tumors (P < .001, Fisher exact test ). In ALK+ ALCL tumors, the mean percentage of cyclin D3-positive tumor cells was 40.6% compared with 5.1% in ALK- ALCL tumors (P < .001, Mann-Whitney U test). The percentages of cyclin D3-positive and pSTAT3-positive tumor cells were positively correlated (Spearman R = 0.35, P = .036). We conclude that cyclin D3 is differentially expressed in ALK+ and ALK- ALCL and that high expression levels of cyclin D3 in ALK+ ALCL may be attributable to STAT3 activation.

p53 gene mutations are uncommon but p53 is commonly expressed in anaplastic large-cell lymphoma

Anaplastic large-cell lymphoma (ALCL), as defined in the World Health Organization, is a heterogeneous category in which a subset of cases is associated with the t(2;5)(p23;q35) or variant translocations resulting in overexpression of anaplastic lymphoma kinase (ALK). p53 has not been assessed in currently defined subsets of ALCL tumors. In this study, we assessed ALK+ and ALK- ALCL tumors for p53 gene alterations using PCR, single-strand conformation polymorphism and direct sequencing methods. We also immunohistochemically assessed ALCL tumors for p53 expression. Three of 36 (8%) ALCL tumors (1/14 ALK+, 2/22 ALK-) with adequate DNA showed p53 gene mutations. By contrast, p53 was overexpressed in 36 of 55 (65%) ALCL tumors (16 ALK+, 20 ALK-). p21, a target of p53, was expressed in 15 of 31 (48%) ALCL tumors including seven of 15 (47%) p53-positive tumors. p21 expression in a subset of ALCL suggests the presence of functional p53 protein. Apoptotic rate was significantly higher in p53-positive than p53-negative tumors (mean 2.78 vs 0.91%, P = 0.0003). We conclude that the p53 gene is rarely mutated in ALK+ and ALK- ALCL tumors. Nevertheless, wild-type p53 gene product is commonly overexpressed in ALCL and may be functional in a subset of these tumors.

High expression of Mcl-1 in ALK positive and negative anaplastic large cell lymphoma

AIM

To gain more insight into the genes involved in the aetiology and pathogenesis of anaplastic large cell lymphoma (ALCL).

METHODS

Serial analysis of gene expression (SAGE) was undertaken on the CD4+ALK+ (anaplastic lymphoma kinase positive) ALCL derived cell line Karpas299 and as comparison on CD4+ T cells. Quantitative reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry were performed on five ALCL derived cell lines and 32 tissue samples to confirm the SAGE data.

RESULTS

High expression of Mcl-1 was seen in the Karpas299 cell line, whereas the two other antiapoptotic Bcl-2 family members, Bcl-2 and Bcl-X(L), were not detected in the SAGE library. Quantitative RT-PCR confirmed the high expression of Mcl-1 mRNA and low expression of Bcl-2 and Bcl-X(L) in Karpas299 and in four other ALCL cell lines. To expand on these initial observations, primary tissue samples were analysed for Mcl-1, Bcl-X(L), and Bcl-2 by immunohistochemistry. All 23 ALK+ and nine ALK- ALCL cases were positive for Mcl-1. Bcl-2 and Bcl-X(L) were expressed infrequently in ALK+ ALCL cases, but were present in a higher proportion of ALK- ALCL cases.

CONCLUSION

The consistent high expression of Mcl-1 in ALK+ and ALK- ALCL suggests that Mcl-1 is the main antiapoptotic protein in this disease. The high frequency of Mcl-1, Bcl-2, and Bcl-X(L) positive ALCL cases in the ALK- group compared with the ALK+ group indicates that ALK induced STAT3 activation is not the main regulatory pathway in ALCL.

Differential Expression of WT1 Gene Product in Non-Hodgkin Lymphomas

The tumor suppressor gene wt1 (Wilms tumor 1) encodes a zinc finger transcription factor reported to be expressed in many tumors, including mesotheliomas, carcinomas, and acute leukemias. However, WT1 expression in non-Hodgkin lymphomas (NHLs) has not been studied. The authors assessed for WT1 expression in six lymphoma/leukemia cell lines using Western blot methods after subcellular fractionation. We also assessed for WT1 expression in 167 NHLs using immunohistochemical methods. The B-cell NHLs analyzed were 18 diffuse large B-cell lymphomas, 13 marginal zone B-cell lymphomas, 9 small lymphocytic lymphomas, (DLBCLs), 8 follicular lymphomas, 6 mantle cell lymphomas, 5 Burkitt lymphomas, 3 lymphoplasmacytic lymphomas, and 2 B-cell lymphoblastic lymphomas. The T-cell NHLs analyzed were 43 anaplastic large cell lymphomas (ALCLs), 26 peripheral T-cell lymphomas unspecified, 13 angioimmunoblastic T-cell lymphomas, 6 cutaneous ALCLs, 6 cases of mycosis fungoides, 5 extranodal NK/T-cell lymphomas of nasal type, and 4 T-cell lymphoblastic lymphomas. WT1 levels were higher in cytoplasmic extracts than in nuclear extracts of the Karpas 299 and SU-DHL-1 lymphoma cell lines but were higher in nuclear extracts than in the cytoplasmic extracts of the Jurkat, HH, U-937, and K562 leukemia cell lines. In NHLs, WT1 was positive in 4 of 5 (80%) Burkitt lymphomas, 9 of 12 (75%) ALK-positive ALCLs, 3 of 6 (50%) lymphoblastic lymphomas (2 of 4 T-cell, 1 of 2 B-cell), 14 of 31 (45%) ALK-negative ALCLs, 6 of 18 (33%) DLBCLs, and 1 of 6 (17%) cutaneous ALCLs. WT1 was negative in all other NHLs tested. WT1 immunoreactivity was primarily cytoplasmic in all positive NHLs except T-cell lymphoblastic lymphoma. In conclusion, WT1 protein is frequently detected in the cytoplasm of a subset of high-grade NHLs.

c-Jun N-terminal kinase (JNK) is required for survival and proliferation of B-lymphoma cells

Several primary murine and human B lymphomas and cell lines were found to constitutively express high levels of the activated form of c-jun N-terminal kinase (JNK), a member of the mitogen-activated protein (MAP) kinase family. Proliferation of murine B lymphomas CH31, CH12.Lx, BKS-2, and WEHI-231 and the human B lymphomas BJAB, RAMOS, RAJI, OCI-Ly7, and OCI-Ly10 was strongly inhibited by SP600125, an anthrapyrazolone inhibitor of JNK, in a dose-dependent manner. The lymphoma cells underwent apoptosis and arrested at the G2/M phase of cell cycle. Furthermore, JNK-specific small interfering RNA (siRNA) inhibited the growth of both murine and human B lymphomas. Thus in the B-lymphoma model, JNK appears to have a unique prosurvival role. Survival signals provided by CD40 and interleukin-10 (IL-10) together reversed the growth inhibition induced by the JNK inhibitor. c-Myc protein levels were reduced in the presence of both SP600125 and JNK-specific siRNA, and CD40 ligation restored c-Myc levels. Moreover, Bcl-xL rescued WEHI-231 cells from apoptosis induced by the JNK inhibitor. The JNK inhibitor also reduced levels of early growth response gene-1 (Egr-1) protein, and overexpressing Egr-1 partially rescued lymphoma cells from apoptosis. Thus, JNK may act via c-Myc and Egr-1, which were shown to be important for B-lymphoma survival and growth.