ALK-positive diffuse large B-cell lymphoma: report of four cases and review of the literature

Acquired resistance to crizotinib in novel CDK14-ALK and CLTC-ALK fusions of ALK-positive large B-cell lymphoma identified by next-generation sequencing

Anaplastic lymphoma kinase-positive large B-cell lymphoma (ALK+ LBCL) is a rare subtype of non-Hodgkin lymphoma. ALK inhibitors are being tried to treat recurrent/refractory ALK+ LBCL. A majority of patients with ALK+ tumors respond to crizotinib, but partial cases ultimately develop resistance about a year later. Here, we report a case of ALK+ LBCL carrying a new fusion gene involving CDK14 and ALK, CLTC-ALK gene rearrangements and MTOR gene mutation. The patient had progressive disease after combination of crizotinib and chemotherapy treatment about 5.5 months later, accompanied by reduced abundance of CDK14-ALK, increased abundance of CLTC-ALK and a novel MFHAS1 gene mutation. However, MTOR mutation turned negative. The patient received alectinib combined with hyper-CVAD, then followed by alectinib as monotherapy for 21 months. The patient achieved partial response and remained in a stable condition. This case suggests that CDK14-ALK fusion gene may be more sensitive to crizotinib than CLTC-ALK fusion gene. MTOR is associated with the anti-tumor mechanism of ALK inhibitors. MFHAS1 gene mutation and/or CLTC-ALK gene copy number amplification may involve resistance to crizotinib. Furthermore, alectinib may inhibit the carcinogenicity of these gene changes and improve the prognosis of ALK+ LBCL.

Lymphoproliferative Neoplasms With Plasmablastic Morphology: An Overview and Diagnostic Approach

CONTEXT.—

Plasmablastic morphology can be seen in several uncommon lymphoproliferative neoplasms. Sometimes it is difficult to distinguish these neoplasms from each other.

OBJECTIVE.—

To review the current understanding of major lymphoproliferative neoplasms with plasmablastic morphology; summarize the clinical, morphologic, immunophenotypic, cytogenetic, and molecular characteristics of each disease entity; and highlight a practical approach for differential diagnosis.

DATA SOURCES.—

Peer-reviewed medical literature and the authors' personal experience.

CONCLUSIONS.—

Plasmablastic lymphoma; plasmablastic myeloma; primary effusion lymphoma; human herpesvirus 8-positive diffuse large B-cell lymphoma, not otherwise specified; and anaplastic lymphoma kinase (ALK)-positive large B-cell lymphoma are major lymphoproliferative neoplasms with plasmablastic morphology. These neoplasms share many common morphologic and immunophenotypic characteristics. Definitive diagnosis requires a thorough understanding of disease phenotype and diagnostic criteria of each category. Recognition of expression pattern of Epstein-Barr virus-encoded small RNA, human herpesvirus 8, and ALK in these neoplasms is critical for diagnosis in cases with typical presentation. Additional ancillary studies and clinical findings may help in difficult cases.

Anaplastic Lymphoma Kinase Positive Large B-Cell Lymphoma: Diagnostic Perils and Pitfalls, an Underrecognized Entity

Anaplastic lymphoma kinase (ALK) positive large B-cell lymphoma (ALK+ LBCL) is an extremely uncommon non-Hodgkin lymphoma (NHL) with a distinctive histomorphologic, immunophenotypic and cytogenetic profile. It is unlike the more common ALK-positive anaplastic large cell lymphoma, although the latter shares the ALK rearrangement pathognomonic for this entity. ALK+ LBCL is an underrecognized entity since it is rare and unfamiliar, and shares morphologic and immunohistochemical features with a variety of other neoplasms that can result in misdiagnosis. This lymphoma exhibits plasmacytoid morphology and negativity for classical immunomarkers of B- and T-cell lineages, and CD30; however, it expresses terminally differentiated B-cell/plasma cell markers such as CD38, CD138, and MUM-1. Precise identification of this entity is pivotal because of its aggressive behaviour, poor response to standard chemotherapy regimens and the potential for the development of novel targeted therapy. A high index of suspicion on morphology and an extensive immunohistochemistry armoury are required for the veracious detection of this lymphoma, especially at extranodal sites. The purpose of bringing forth this present case, an extranodal neoplasm with plasmacytoid morphology at vertebral location in a young adult, is to highlight the diagnostic perils and pitfalls, the clues to unravel the quandaries and thus, the incredible utility of histopathological examination and immunohistochemical analysis in attaining the unerring diagnosis.

Anaplastic lymphoma kinase-positive large B-cell lymphoma (ALK + LBCL): a systematic review of clinicopathological features and management

Anaplastic lymphoma kinase-positive (ALK+) large B-cell lymphoma (LBCL) is a rare CD20-negative aggressive lymphoma. Given its rarity, data on ALK + LBCL are scarce and limited to case reports and small case series. Our systematic review included 184 unique cases published in the literature and shows that ALK + LBCL can affect individuals at any age, has a male predominance and is not associated with chronic viral infections. The malignant cells express ALK, VS38c, BLIMP-1, EMA, c-MYC, and BOB-1. The STAT3/STAT5, PI3K/AKT, PLCG2, and ERK pathways are important in the pathophysiology of ALK + LBCL. The prognosis of ALK + LBCL is poor with a 5-year survival rate of 28%. Early disease stage is associated with better outcomes. ALK inhibitors and other targeted agents could be of value in the treatment of ALK + LBCL. Additional research is needed to better understand, diagnose and treat ALK + LBCL.

Diagnosis and treatment of pediatric anaplastic lymphoma kinase-positive large B-cell lymphoma: A case report

BACKGROUND

Anaplastic lymphoma kinase-positive (ALK+) large B-cell lymphoma (LBCL) is a rare type of lymphoma with high invasiveness and rapid progression. It occurs in all age groups, but is extremely rare in children. The lesions mainly involve the lymph nodes and may present with extra-nodal involvement. Response to conventional chemotherapies and local radiotherapy is poor, with a 5-year overall survival of less than 40%. Recently, the use of ALK inhibitors for the treatment of this disease has been reported.

CASE SUMMARY

We present a case of a 12-year-old boy diagnosed with ALK+LBCL. The patient had a 2-mo medical history of a calvarial mass, extensive systemic involvement, and positive bone marrow clathrin heavy chain (CLTC)-ALK fusion gene. Complete remission 1 (CR1) was achieved using the modified LMB89 Group C regimen followed by autologous stem cell transplantation. The patient relapsed 3 mo later. He then achieved CR2 with three short courses of chemotherapy (COP, reduced-dose ICE, low-dose Ara-c+VP16) and continuous alectinib targeted therapy. Afterward, allogeneic hematopoietic stem cell transplantation (allo-HSCT) was performed. At 16 mo after the allo-HSCT, the patient was still in CR2.

CONCLUSION

The modified LMB89 Group C regimen and ALK inhibitors are effective. Allo-HSCT should be performed after remission.

Stance of MRD in Non-Hodgkin's Lymphoma and its upsurge in the novel era of cell-free DNA

Cancer genomics has evolved over the years from understanding the pathogenesis of cancer to screening the future possibilities of cancer occurrence. Understanding the genetic profile of tumors holds a prognostic as well as a predictive value in this era of therapeutic surveillance, molecular remission, and precision medicine. Identifying molecular markers in tumors is the current standard of approach, and requires an efficient combination of an accessible sample type and a profoundly sensitive technique. Liquid biopsy or cell-free DNA has evolved as a novel sample type with promising results in recent years. Although cell-free DNA has significant role in various cancer types, this review focuses on its application in Non-Hodgkin's Lymphoma. Beginning with the current concept and clinical relevance of minimal residual disease in Non-Hodgkin's lymphoma, we discuss the literature on circulating DNA and its evolving application in the realm of cutting-edge technology.

CRISPR genome editing of murine hematopoietic stem cells to create Npm1-Alk causes ALK+ lymphoma after transplantation

CRISPR/Cas9 genomic editing of wild-type hematopoietic stem cells generates Npm1-Alk, leading to ALK+ large-cell lymphomas in recipients. CD30+ postthymic T-cell lymphomas are polyclonal but transplantable to secondary recipients with long latency.

The Minimal Residual Disease in Non-Hodgkin's Lymphomas: From the Laboratory to the Clinical Practice

Minimal residual disease (MRD) in non-Hodgkin's lymphomas (NHLs) still represents matter of interest and debate: indeed, the new available treatments offer higher rates of complete responses and MRD negativity than in the past, with a positive impact on the long-term survival. Furthermore, the introduction of more sensitive and accurate molecular techniques, such as digital PCR (ddPCR) and the next generation sequencing techniques (NGS), increased the possibility of identifying molecular targets to be followed after therapy (such as rearrangement of immunoglobulins, fusion genes, or mutations). This review focused on how molecular biology can help to detect MRD in different types of NHLs and how MRD can change the clinical practice in 2019. In follicular lymphoma (FL), contamination of the grafts and molecular disease persistence after transplantation represent a negative prognostic factors. The combination of Rituximab or Obinutuzumab with Bendamustine seems to be the most effective way to clear MRD in FL patients receiving chemo-immunotherapy (further studies are in progress), and also ⁹⁰Yttrium-Ibritumomab-Tiuxetan offers a deep clearance of molecular disease. Finally, molecular MRD can further stratify PET-negative cases, with subjects both PET- and MRD-negative presenting the best outcome. In aggressive lymphomas, MRD has a relevant prognostic power and can represent the platform for immunotherapy (such as CAR-T). In diffuse large B-cell lymphoma (DLBCL), the assessment of MRD in the plasma (where cell-free DNA and exosomes circulate) seems to be more predictive than the bone marrow analysis or peripheral blood mononuclear cells. Finally, NGS technologies could be more useful than the classical "patient allele-specific PCR" because they can identify any possible clone emerging during the treatment or follow-up, even if different from that identified at diagnosis, thus predicting relapse. After all, the present available molecular approaches can move MRD from the bench side to the clinical practice.

Anaplastic lymphoma kinase-positive large B-cell lymphoma with a diagnostic pitfall of carcinoma: a case report

Anaplastic lymphoma kinase-positive large B-cell lymphoma (ALK+LBCL) is a rare non-Hodgkin lymphoma that exhibits a characteristic immunoblastic/plasmablastic morphology and is frequently expressing Clathrin-anaplastic lymphoma kinase fusion protein. Since being negative for T- and B- linage markers, this tumor is easy to be misdiagnosed, especially when it has unusual morphology and immunophenotype. Here, we report an ALK+LBCL with a diagnostic pitfall of carcinoma. The patient was a 28-year-old man with enlargement of a right submandibular lymph node. Morphologically, the lymph node had an unusual nodular growth pattern, with nodules surrounded by collagen bands. The neoplastic cells expressed epithelial membrane antigen, CD138, CD38, Mum-1, but negative for T- and B- linage markers, and showed a strong granular cytoplasmic Anaplastic Lymphoma Kinase staining pattern. Some tumor cells had the expressing of Cytokeratin.

ALK-positive Large B-cell Lymphoma: A Clinicopathologic Study of 26 Cases With Review of Additional 108 Cases in the Literature

Anaplastic lymphoma kinase-positive large B-cell lymphoma (ALK LBCL) is a rare, aggressive subtype of diffuse large B-cell lymphoma with characteristic ALK rearrangements. Diagnosis of ALK LBCL can be challenging because of its rarity, unique morphologic characteristics, and unusual immunophenotypic features, which significantly overlap with other hematologic and nonhematologic neoplasms. The purpose of this study is to further explore the clinicopathologic features of ALK LBCL to ensure the awareness and accurate diagnosis of this entity. We retrospectively reviewed the data from 26 cases in our institutions and additional 108 cases from the literature. ALK LBCL typically occurred in the lymph nodes of young and middle-aged, immunocompetent patients. The medium age was 35 years with a male to female ratio of 3.5:1. Vast majority of cases showed immunoblastic and/or plasmablastic morphology. All cases expressed ALK protein with a cytoplasmic granular pattern in most of them. Common B-cell markers (CD20, CD79a, and PAX5) were typically negative, but the tumor cells mostly expressed 2 B-cell transcriptional factors, BOB1 and OCT2. The 5-year overall survival (OS) was 34%, and the median survival was 1.83 years. In patients with stage III/IV disease, the 5-year OS was only 8%. Moreover, patients below 35 years of age had a significantly better OS than those aged 35 years or above.

Anaplastic lymphoma kinase-positive large B-cell lymphoma: Clinico-pathological study of 17 cases with review of literature

We retrospectively analysed 17 cases of anaplastic lymphoma kinase-positive large B-cell lymphoma (ALK+, LBCL) according to the morphological, immunohistochemical, molecular and clinical features, using which we intend to elucidate the clinicopathological characteristics of this rare entity. In this study, all cases de facto share common features that defined them as a single entity, and various characteristics may expand the spectrum. Among 15 cases, 60% followed an aggressive clinical course with advanced stage and high IPI scores; the median survival of these patients was only 8 months. An analysis showed that both the IPI score and the Ann Arbor stage were significant prognostic factors. Most patients received a chemotherapy regimen including CHOP, CHOEP, EPOCH, and CVAD, and some also underwent localized radiotherapy. However, ALK+, LBCL cases display a dismal clinical outcome and can only be cured with conventional chemotherapy protocols at the stage of localized disease. Novel front-line intensive chemotherapy regimens should therefore be evaluated in this group of patients.

Cytologic perspectives on neoteric B-cell lymphoproliferative disorders

The 2008 World Health Organization (WHO) classification of hematopoietic and lymphoid tissues has been recently revised, and publication of the updated 2016 version is expected soon. Given that cytopathologists are often involved in the diagnosis of primary, recurrent, and transformed lymphoproliferative disorders, knowledge of updates to the WHO lymphoma classification, including terminology, pathogenesis, ancillary techniques, and targeted therapies is necessary. Herein, we reference the last decade of cytology specific literature for seven newer B-cell disorders and provide illustrative examples of each entity from our files.

Anaplastic lymphoma kinase positive large B-cell lymphoma: Literature review and report of an endoscopic fine needle aspiration case with tigroid backgrounds mimicking seminoma

Anaplastic lymphoma kinase-positive large B-cell lymphoma (ALK+ LBCL) is a rare distinct type of non-Hodgkin's lymphoma that arises in association with alterations of the ALK gene. This distinct disease entity is typically associated with an aggressive clinical course and appears in light microscopic preparations as a monomorphic population of large, immunoblast-like cells. In this report, we describe a case of ALK+ LBCL diagnosed by transgastric endoscopic ultrasound-guided fine needle aspiration (EUS FNA) of splenic hilar lymph nodes. Modified Giemsa stained direct smears from the FNA sample demonstrated large lesional cells with foamy cytoplasm and macronucleoli admixed with small lymphocytes in tigroid backgrounds, mimicking the cytologic appearance of seminoma. Ancillary immunohistochemical studies subsequently confirmed the diagnosis of ALK+ LBCL with the lesional cells being immunoreactive for CD138, VS38c, MUM1, ALK1, and lambda light chain. The cohesiveness of the cells, the cellular morphology, and the tigroid backgrounds were all pitfalls for accurate diagnosis of this rare specific type of lymphoid malignancy by cytology. To our knowledge this is the first case report detailing the diagnosis of ALK+ LBCL by EUS FNA and the first report describing a glycogen-rich tigroid background in direct FNA smears. Establishing a refined diagnosis in cases of this rare form of LBCL is necessary, as therapies targeting ALK may be of value in clinical management. Diagn. Cytopathol. 2017;45:148-155. © 2016 Wiley Periodicals, Inc.

Oct2 and Bob1 are sensitive and specific markers in lineage determination of B cell lymphomas with no expression of conventional B cell markers

AIMS

Rare cases of B cell lymphomas do not express conventional B cell markers (CD20, CD79a and PAX5), and these types of lymphomas include anaplastic lymphoma kinase (ALK)-positive large B cell lymphoma, plasmablastic lymphoma, primary effusion lymphoma and the solid variant of primary effusion lymphoma, extracavitary human herpesvirus 8 (HHV8)-positive large B cell lymphoma. Establishing accurate diagnoses of these B cell lymphomas can be challenging, and often requires a large panel of immunohistochemical stains, molecular assays and cytogenetic studies. B cell-specific transcription factors, Oct2 and Bob1, have been shown to be expressed consistently in most, if not all, B cell lymphomas, and therefore we investigated the utility of Oct2 and Bob1 immunohistochemistry in lineage determination of the aforementioned B cell lymphomas.

METHODS AND RESULTS

We selected 34 cases of previously diagnosed B cell lymphomas with no or weak expression of CD20, CD79a and PAX5. Oct2 and Bob1 were positive in 74% (25 of 34) and 85% (29 of 34) of the cases, respectively. When we combined the results of these two immunostains, 94% (32 of 34) cases expressed at least one of these two markers. We also included 51 control cases of non-B cell neoplasms, and none of them expressed either Oct2 or Bob1.

CONCLUSIONS

Oct2 and Bob1 are very reliable in determining B cell lineage in the absence of expression of other pan-B cell markers, and it should provide great diagnostic benefit to include them both in a panel of immunohistochemistry to assess undifferentiated malignant neoplasms.

Recent Advances in Aggressive Large B-cell Lymphomas: A Comprehensive Review

Diffuse large B-cell lymphoma (DLBCL) is an aggressive disease with considerable heterogeneity reflected in the 2008 World Health Organization classification. In recent years, genome-wide assessment of genetic and epigenetic alterations has shed light upon distinct molecular subsets linked to dysregulation of specific genes or pathways. Besides fostering our knowledge regarding the molecular complexity of DLBCL types, these studies have unraveled previously unappreciated genetic lesions, which may be exploited for prognostic and therapeutic purposes. Following the last World Health Organization classification, we have witnessed the emergence of new variants of specific DLBCL entities, such as CD30 DLBCL, human immunodeficiency virus-related and age-related variants of plasmablastic lymphoma, and EBV DLBCL arising in young patients. In this review, we will present an update on the clinical, pathologic, and molecular features of DLBCL incorporating recently gained information with respect to their pathobiology and prognosis. We will emphasize the distinctive features of newly described or emerging variants and highlight advances in our understanding of entities presenting a diagnostic challenge, such as T-cell/histiocyte-rich large B-cell lmphoma and unclassifiable large B-cell lymphomas. Furthermore, we will discuss recent advances in the genomic characterization of DLBCL, as they may relate to prognostication and tailored therapeutic intervention. The information presented in this review derives from English language publications appearing in PubMed throughout December 2015. For a complete outline of this paper, please visit: http://links.lww.com/PAP/A12.

An unusual case of anaplastic lymphoma kinase-positive large B-cell lymphoma in an elderly patient: A case report and discussion

We present an unusual case of anaplastic lymphoma kinase (ALK)-positive large B-cell lymphoma, with rapid clinical progression, which occurred in a 90-year-old male patient. The patient presented with numerous enlarged lymph nodes in the neck and mediastinum. Histopathological analysis of a single lymph node detected diffuse large immunoblastic- or plasmablastic-like tumor cells, which were strongly immunoreactive for ALK in a granular cytoplasmic distribution, but negative for the expression of CD20 and CD79a. In addition, polymerase chain reaction assays were unable to detect clonal rearrangements of the T cell receptor-γ and immunoglobulin heavy chain genes in the tumor lesion, and in situ hybridization tested negative for infection with Epstein-Barr virus. The patient underwent a single cycle of chemotherapy using the cyclophosphamide, doxorubicin, vincristine, prednisone, and etoposide (E-CHOP) regimen; however, the patient developed pleural effusions with respiratory distress, associated with clinical deterioration. The patient succumbed to the disease within 4 months of initial presentation. To the best of our knowledge, this is the eldest patient with this type of lymphoma to be reported in the literature.

Human immunodeficiency virus associated plasmablastic lymphoma: A case report

Non-Hodgkin's lymphoma (NHL) is the third common malignant lesion of the oral region. Plasmablastic lymphomas are rare, aggressive neoplasms occurring mostly in human immunodeficiency virus (HIV) infected individual which accounts for approximately 2.6% of all NHL. It usually presents as a diffuse growth and with diffuse pattern of histological presentation. It is very difficult to differentiate this lymphoma from other NHL. Immunohistochemical evaluation of various markers is an important criteria of the diagnostic protocol. Here, we describe a case of plasmablastic lymphoma in a 50-year-old female HIV-infected patient. The diagnosis was based on histopathological examination and immunophenotyping.

Hematolymphoid lesions of the sinonasal tract

Various hematolymphoid lesions involve the sinonasal tract, including aggressive B, T, and NK-cell neoplasms; myeloid sarcoma; low-grade lymphomas; indolent T-lymphoblastic proliferations; and Rosai-Dorfman disease. Differentiating aggressive lymphomas from non-hematopoietic neoplasms such as poorly differentiated squamous cell carcinoma, olfactory neuroblastoma, or sinonasal undifferentiated carcinoma may pose diagnostic challenges. In addition, the necrosis, vascular damage, and inflammatory infiltrates that are associated with some hematolymphoid disorders can result in misdiagnosis as infectious, autoimmune, or inflammatory conditions. Here, we review hematolymphoid disorders involving the sinonasal tract including their key clinical and histopathologic features.

Anaplastic lymphoma kinase-positive diffuse large B-cell lymphoma presenting in nasal cavity: a case report and review of literature

Anaplastic lymphoma kinase (ALK)-positive diffuse large B-cell lymphoma (DLBCL) is a rare subtype of non-Hodgkin's lymphoma (NHL) with distinct morphologic and immunohistochemical features. We reported a 57-year-old female with ALK-positive DLBCL in her left nasal cavity. Histologically, the tumor cells were characterized by plasmablastic morphology and tested positive for ALK in a cytoplasmic granular staining pattern. The neoplastic cells were positive for CD38, CD4, MUM1, CD138 and Vimentin. However, they failed to express CD56, CD30, as well as mature B cells markers, such as CD79a, CD20 and T cells markers such as CD2, CD3, CD5, CD7 and CD8. The patient achieved complete response after four cycles of CHOEP (cyclophosphamide, doxorubicin, vincristine, prednisone, and etoposide) treatment. Then she received radiotherapy of the originally involved area. This case represented a rare ALK-positive DLBCL in the nasal region.

ALK-positive cancer: still a growing entity

 Since the discovery of ALK-positive anaplastic large-cell lymphoma in 1994 many other types of tumors showing ALK expression were disclosed. They form a heterogeneous group, including lung, renal and soft tissue tumors. The biological function of ALK, its role in carcinogenesis and impact exerted on the clinical outcome have been studied by many research groups. New drugs specifically dedicated for ALK inhibition, for example, crizotinib, have been synthesized and have become a viable treatment option for ALK-positive lung adenocarcinoma, and potentially for other ALK-positive cancers. This review summarizes the current state of knowledge concerning ALK-positive neoplasms, focusing on the clinical aspects of the subject.

ALK-positive diffuse large B-cell lymphoma of the duodenum: A case report and review of the literature

Anaplastic lymphoma kinase (ALK)-positive diffuse large B-cell lymphoma (ALK⁺ DLBCL) is characterized by the presence of immunoblastic or plasmablastic cells with a strong ALK protein expression that is frequently associated with t(2;17)(p23;q23). The present study reports a case of ALK⁺ DLBCL in a 26-year-old male with a duodenal mass. Histologically, the neoplastic cells demonstrated prominent plasmablastic differentiation with abundant amphophilic cytoplasma and central nucleoli. Paraffin immunohistochemistry revealed: an exclusively cytoplasmic granular expression of ALK; CD138, immunoglobulin A (IgA) and CD79α positivity; and focal expression of multiple myeloma oncogene 1 (Mum-1), CD30 and epithelial membrane antigen (EMA). However, the immunohistochemical staining was negative for CD3, CD38 and CD20. Fluorescence in situ hybridization (FISH) analysis using an ALK break-apart probe revealed the presence of ALK gene rearrangements in the patient. To the best of our knowledge, the current case represents the first example of primary extranodal ALK⁺ DLBCL presenting as a duodenal mass.

Anaplastic lymphoma kinase-positive large B-cell lymphoma: description of a case with an unexpected clinical outcome

Anaplastic lymphoma kinase-positive (ALK-positive) large B-cell lymphoma is a rare and aggressive variant of large B-cell lymphoma (LBCL), first reported by Delsol et al in 1997, showing distinctive morphologic, immunophenotypic and cytogenetic features. The latest 2008 World Health Organization Classification of Tumours of Haematopoietic and Lymphoid tissues recognizes ALK-positive LBCL as a separate entity. Here, we report a case of ALK-positive large B-cell lymphoma in a 53-year-old man with diffuse abdominal and mediastinal lymph-nodes involvement. According to the Ann Arbor staging system, the patient had a stage IIIB lymphoma. The age-adjusted International Prognostic Index was 2 (stage III and elevated lactate dehydrogenase), so the disease was considered high risk. The patient underwent chemotherapy, radiotherapy, and an autologous stem cell transplantation. The patient is alive and free of disease 35 months after diagnosis.

ALK-driven tumors and targeted therapy: focus on crizotinib

Receptor tyrosine kinases have emerged as promising therapeutic targets for a diverse set of tumors. Overactivation of the tyrosine kinase anaplastic lymphoma kinase (ALK) has been reported in several types of malignancies such as anaplastic large cell lymphoma, inflammatory myofibroblastic tumor, neuroblastoma, and non-small-cell lung carcinoma. Further characterization of the molecular role of ALK has revealed an oncogenic signaling signature that results in tumor dependence on ALK. ALK-positive tumors display a different behavior than their ALK-negative counterparts; however, the specific role of ALK in some of these tumors remains to be elucidated. Although more studies are required to establish selective targeting of ALK as a definitive therapeutic option, initial trials have shown extraordinary results in the majority of cases.

Anaplastic lymphoma kinase-positive large B-cell lymphoma: a case report with emphasis on the cytological features of the pleural effusion

Anaplastic lymphoma kinase (ALK)-positive large B-cell lymphoma (ALK-positive LBCL) is an extremely rare distinct clinicopathological subtype of LBCL, characterized by the presence of ALK-positive monomorphic large immunoblast-like neoplastic B cells. Herein, we describe the first cytological report on ALK-positive LBCL in the pleural effusion. A 69-year-old Japanese male with a past history of malignant lymphoma of the cecum presented with progressive dyspnea and pleural effusion. Removal of the pleural effusion and aspiration of bone marrow were performed. May-Grünwald-Giemsa stain of the pleural fluid revealed abundant single or small aggregates of large-sized round cells. These cells had centrally-located large round to oval nuclei. The peculiar finding was the presence of pseudopodial cytoplasmic projections, and some neoplastic cells had eosinophilic pseudopodial cytoplasmic projections, which resembled "flaming plasma cells". Histopathological and immunohistochemical studies of the bone marrow demonstrated CD138(+), ALK1(+), CD20(-), CD79a(-), CD30(-), and IgA(+) large-sized neoplastic cells. Therefore, a diagnosis of ALK-positive LBCL was made. The peculiar finding of the present case was that most of the neoplastic cells had pseudopodial cytoplasmic projections, and some of them had eosinophilic pseudopodial cytoplasmic projections that resembled "flaming plasma cells", which has been recognized as the characteristic finding of IgA myeloma. Therefore, tumor cells that resembled "flaming plasma cells" in the pleural effusion may have had IgA in the cytoplasm. Albeit extremely rare, ALK-positive LBCL shows aggressive clinical course, thus, recognition of the cytomorphological features of this type of malignant lymphoma is important for early and correct diagnosis.

ALK-positive large B-cell lymphomas express a terminal B-cell differentiation program and activated STAT3 but lack MYC rearrangements

ALK-positive large B-cell lymphoma is an aggressive lymphoid neoplasm characterized by a monomorphic proliferation of immunoblast-like cells expressing a plasmablastic phenotype and carrying ALK rearrangements. MYC rearrangements are frequent in plasmablastic lymphomas, advanced plasma cell myelomas and a subgroup of diffuse large B-cell lymphomas, but their presence in ALK-positive large B-cell lymphomas is unknown. MYC expression is downregulated by BLIMP1, a master modulator of plasma cell differentiation. BLIMP1 and MYC are upregulated by STAT3, a signal transducer activated by ALK. To determine the role of BLIMP1, MYC and STAT3 in the pathogenesis of ALK-positive large B-cell lymphomas, we investigated MYC rearrangement and the expression of MYC, phosphorylated STAT3, BLIMP1, PAX5 and XBP1 in 12 ALK-positive large B-cell lymphomas. All cases expressed ALK with a granular cytoplasmic pattern. Nine cases had a split signal consistent with an ALK rearrangement. Three additional cases showed a deletion of the 5' or 3' end of the ALK probe consistent with cryptic translocation. PAX5 was virtually negative in all cases tested, whereas BLIMP1 was expressed in all tumors and XBP1 in 11 of 12. Phosphorylated STAT3 was observed in all cases with a strong and diffuse nuclear pattern. MYC rearrangements were not identified in any tumor, but MYC gains and amplification were detected in six cases and one case, respectively. MYC protein was expressed in all tumors independently of MYC gene alterations. These results indicate that ALK-positive large B-cell lymphomas express a complete plasmablastic differentiation program but, contrary to plasmablastic lymphomas, do not have MYC rearrangements. STAT3 is constantly activated and may be an alternative mechanism to promote MYC expression in these tumors. The relevance of the ALK/STAT3 pathway in the pathogenesis of ALK-positive large B-cell lymphomas may offer an attractive target for new therapies.

Clinical Significance of ALK-1 Gene Abnormalities in Diffuse Large Cell Lymphoma

Objectives

To detect relative frequency of anaplastic lymphoma kinase (ALK-1) gene abnormality in diffuse large cell lymphoma (DLCL) using fluorescence in situ hybridization (FISH), and correlate its presence with clinicopathological features which may be useful for choice of therapy and predict survival in newly diagnosed cases.

Patients and methods

A prospective study was done between March 2004 and October 2009. Fifty patients newly diagnosed with DLCL were enrolled into the study. Immunophenotyping was done and detection of ALK-1 gene abnormalities were carried out by immunohistochemically (IHC) and FISH. Patients that proved to be ALK-1 positive were treated with standard cyclophosphamide –hydroxy-daunorubicin- oncovin-prednisone (CHOP) protocol.

Results

All ALK +ve patients achieved complete remission (CR) vs. 93.5% CR and 6.5% partial remission (PR) for ALK −ve patients respectively. Disease free survival (DFS) at 24 months was 81.8% in the CHOP-14 group (ALK-1⁻) vs. 100% for the CHOP-21 group (ALK-1⁺). Overall survival (OS) at 30 months was 80.4% in the CHOP-14 group vs. 100% for the CHOP-21 group.

Targeting ALK: a promising strategy for the treatment of non-small cell lung cancer, non-Hodgkin's lymphoma, and neuroblastoma

Anaplastic lymphoma kinase (ALK) is a tyrosine kinase receptor that affects a number of biological and biochemical functions through normal ligand-dependent signaling. It has oncogenic functions in a number of tumors including non-small cell lung cancer (NSCLC), anaplastic large cell lymphoma, and neuroblastoma when altered by translocation or amplification or mutation. On August 2011, a small molecule inhibitor against ALK, crizotinib, was approved for therapy against NSCLC with ALK translocations. As we determine the molecular heterogeneity of tumors, the potential of ALK as a relevant therapeutic target in a number of malignancies has become apparent. This review will discuss some of the tumor types with oncogenic ALK alterations. The activity and unique toxicities of crizotinib are described, along with potential mechanisms of resistance and new therapies beyond crizotinib.

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.

Pediatric anaplastic lymphoma kinase-positive large B-cell lymphoma: a case report and review of the literature

We present a case of pediatric anaplastic lymphoma kinase-positive large B-cell lymphoma (ALK-positive LBCL) with a cervical, mesentery, and pelvis cavity mass. Histologic examination of the cervical mass revealed that the lesion was composed of diffuse large immunoblastic-like or plasmablastic-like tumor cells with a sinusoidal growth pattern. The tumor cells were strongly immunoreactive for ALK; revealed a granular cytoplasmic distribution; and were diffusely positive for CD45, CD4, CD138, epithelial membrane antigen, and multiple myeloma oncogene-1 but negative for CD20 and CD79a. The patient underwent 5 courses of cyclophosphamide, doxorubicin, vincristine, prednisone, and etoposid and obtained a remarkable clinical response with regression of mesentery and pelvis cavity mass. We suggest that this distinct subtype of large B-cell lymphoma should belong to the spectrum of pediatric lymphomas and that radiologic examination should be performed to inspect the progression of disease even if the patients experienced complete remission at initial chemotherapy.

Inhibitors of the anaplastic lymphoma kinase

INTRODUCTION

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase normally expressed in the developing nervous tissue. Genetic alterations of ALK are associated with a number of cancers, including anaplastic large cell lymphoma (ALCL) and a subset of non-small cell lung cancer (NSCLC). Standard therapies for these diseases include surgery plus unspecific cytotoxic agents, with a low therapeutic window and significant treatment-associated systemic toxicity. A few small-molecule inhibitors of ALK kinase activity have been described in the recent years, some of which are currently undergoing clinical evaluation.

AREAS COVERED

Literature was searched for all ALK inhibitors that have entered clinical investigation, including published research articles and meeting abstracts. Data on pharmacokinetics, safety and efficacy of crizotinib, as well as preliminary clinical data for second-generation compounds, are reviewed. The issue of drug resistance is discussed.

EXPERT OPINION

Understanding the specific genetic aberration that causes cancer development and progression allows major advances in cancer therapy. Along the same way shown by imatinib in chronic myeloid leukemia, compounds that selectively target ALK are bringing a revolution in the treatment of ALK-positive tumors. Crizotinib has just been approved, and new more potent ALK inhibitors will shortly follow. These molecules represent another excellent proof-of-principle for targeted therapy.

Pediatric T-cell prolymphocytic leukemia with an isolated 12(p13) deletion and aberrant CD117 expression

T-cell Prolymphocytic leukemia (T-PLL) is a rare post-thymic T-cell malignancy that follows an aggressive clinical course. The classical presentation includes an elevated white blood cell (WBC) count with anemia and thrombocytopenia, hepatosplenomegaly, and lymphadenopathy. T-PLL is a disease of the elderly and to our knowledge it has never been described in the pediatric age group. We report a case of T-PLL in a 9 year old male who was initially diagnosed with T-cell acute lymphoblastic lymphoma (ALL), the diagnosis was later refined to T-PLL following additional analysis of bone marrow morphology and immunophenotype. Two unusual findings in our patient included CD117 expression and an isolated chromosomal 12(p13) deletion. The patient failed to respond to standard ALL induction chemotherapy, but achieved complete remission following treatment with a fludarabine and alemtuzumab-based regimen.

Anaplastic lymphoma kinase-positive large B-cell lymphoma: an underrecognized aggressive lymphoma

Anaplastic lymphoma kinase-(ALK-) positive large B-cell lymphoma (ALK+ LBCL) is a rare, aggressive tumor characterized by an immunoblastic or plasmablastic morphologic appearance, expression of ALK, CD138, CD45, EMA, and often IgA by immunohistochemistry, and characteristic chromosomal translocations or rearrangements involving the ALK locus. The morphologic and immunophenotypic overlap of this tumor with other hematologic and nonhematologic malignancies may result in misdiagnosis. The tumor has been identified in both pediatric and adult populations and demonstrates a male predominance. Presentation is most often nodal, particularly cervical. No association with immunocompromise or geographic location has been recognized. The most common gene rearrangement is between clathrin and ALK (t(2;17)(p23;q23)), resulting in the CLTC-ALK chimeric protein, although other fusions have been described. Response to conventional chemotherapy is poor. The recent introduction of the small molecule ALK inhibitor, crizotinib, may provide a potential new therapeutic option for patients with this disease.

Large B-cell lymphomas with plasmablastic differentiation: a biological and therapeutic challenge

Plasmablastic differentiation can be found in a variety of large B-cell lymphomas, including plasmablastic lymphoma, ALK-positive large B-cell lymphoma, primary effusion lymphoma, large B-cell lymphoma arising in human herpesvirus-8 (HHV-8)-associated multicentric Castleman disease and diffuse large B-cell lymphoma (DLBCL) with partial plasmablastic phenotype. These tumors are characterized by acquisition of the transcriptional profile of plasma cells (with overexpression of PRDM1/Blimp1 and XBP1s, in concert with extinction of the B-cell differentiation program) by proliferating immunoblasts. This particular biological entity, i.e. large B-cell lymphoma with plasmablastic differentiation, is almost always associated with an aggressive clinical behavior. This review summarizes the current knowledge of the biological basis of plasmablastic differentiation in large B-cell lymphomas, the diagnostic borders with DLBCL and multiple myeloma, the associated adverse molecular events (with concomitant MYC, p53 and ALK alterations) and the potential therapeutic targets so far identified (including the unfolded protein response pathway). The highly aggressive nature of these lymphomas and the relative paucity of molecular data available highlight the need for deeper insights into the molecular pathogenesis of large B-cell lymphomas with plasmablastic differentiation in order to identify new and effective alternative treatments.

ALK-positive extramedullary plasmacytoma with expression of the CLTC-ALK fusion transcript

Anaplastic lymphoma kinase (ALK)-positive non-Hodgkin lymphoma (NHL) was long thought to be a disease occurring uniquely in T or null-cell lymphomas. More recently, however, a small number of B-lineage lymphomas have been reported to express ALK fusion genes. These tumors often exhibit a plasmablastic morphology, a finding which prompted our interest in looking for ALK fusions in plasma cell neoplasms. We studied 46 cases of extramedullary plasmacytoma by immunostaining with anti-ALK antibody and fluorescence in situ hybridization (FISH) analysis using an ALK break-apart probe and found one case to be ALK protein-positive and demonstrated the disruption of the ALK gene in this case. Immunohistochemistry showed that the tumor cells were strongly positive for CD138, VS38c, and epithelial membrane antigen, but lacked expression of CD20, CD79a, CD45, and CD30. Both RT-PCR and genomic DNA-PCR confirmed the CLTC-ALK fusion. This finding expands the lists of the ALK-positive tumors, and ALK-positive extramedullary plasmacytoma may benefit from the treatment of ALK inhibitor in the future.

Functions and uses of immunohistochemical stains in cutaneous infiltrates of hematopoietic origin: a review for the practicing dermatologist

BACKGROUND

Immunohistochemical stains, particularly those for cutaneous lymphomas, have similar-sounding names, which may lead to confusion among dermatologists who are not well versed in the terminology of the tools used for pathologic diagnosis. Also aiding in this is the fact that some familiar stains are constantly investigated for novel utility in different tumors, and a plethora of new stains regularly emerge in the peer-reviewed literature.

OBJECTIVE

To review the major stains encountered in dermatopathologic reports for cutaneous lymphomas. A select number of other stains are reviewed that are either new and under investigation in several cutaneous processes or have a new use described in recent reports.

METHODS

The peer-reviewed literature was searched and analyzed for the accepted purposes of using these markers.

RESULTS

All pertinent findings for these immunostains are reported with the purpose of educating the dermatology community.

CONCLUSION

This review serves as a reference to clarify potentially confusing immunohistochemical stains.

Inhibition of anaplastic lymphoma kinase (ALK) activity provides a therapeutic approach for CLTC-ALK-positive human diffuse large B cell lymphomas

ALK positive diffuse large B-cell lymphomas (DLBCL) are a distinct lymphoma subtype associated with a poor outcome. Most of them feature a t(2;17) encoding a clathrin (CLTC)-ALK fusion protein. The contribution of deregulated ALK-activity in the pathogenesis and maintenance of these DLBCLs is not yet known. We established and characterized the first CLTC-ALK positive DLBCL cell line (LM1). LM1 formed tumors in NOD-SCID mice. The selective ALK inhibitor NVP-TAE684 inhibited growth of LM1 cells in vitro at nanomolar concentrations. NVP-TAE684 repressed ALK-activated signalling pathways and induced apoptosis of LM1 DLBCL cells. Inhibition of ALK-activity resulted in sustained tumor regression in the xenotransplant tumor model. These data indicate a role of CLTC-ALK in the maintenance of the malignant phenotype thereby providing a rationale therapeutic target for these otherwise refractory tumors.