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PubMed2006

Cutaneous presentation on the eyelid of primary, systemic, CD30+, anaplastic lymphoma kinase (ALK)-negative, anaplastic large-cell lymphoma (ALCL).

AIM: To report an unusual case of cutaneous presentation on the eyelid of systemic (or nodal), CD30+, anaplastic large-cell lymphoma (ALCL). METHODS: A 39-year-old man presented with a rapidly growing exophytic mass on the left upper eyelid, with a protuberant, ulcerated aspect and with discharge. The patient showed lymph node involvement 3 months after the appearance of the lesion on the eyelid (the lesion itself appeared 1 week before examination). RESULTS: The histopathologic and immunohistochemical diagnosis was ALCL, T-cell phenotype, strongly positive for CD43 and CD30, and negative for CD3, anaplastic lymphoma kinase (ALK), and B-cell antigens. Treatment was by radiotherapy and, later, chemotherapy (cyclophosphamide, adriamycin, vincristine, and prednisolone, CHOP) for skin recurrences and lymphadenopathies over 5 years. There has been no recurrence for more than 6 years. CONCLUSIONS: Primary, systemic, CD30+, ALK-negative, ALCL presentations generally have a poor prognosis and tend to occur in older individuals, although the clinical outcome is highly variable and difficult to predict in individual cases. Only three cases of ALCL have been described in the ocular adnexae and none was ALK-negative.

Adult↗

PubMed1995

CD44v6 is a marker for systemic spread in cutaneous T-cell lymphomas. A comparative study between nodal and cutaneous lymphomas.

Adhesion molecules are involved in leukocyte recruitment, lymphocyte recirculation, and in several aspects of tumour biology. Recent discoveries of surface proteins on tumour cells involved in tumour metastasis may explain the invasive behaviour, the migration involving reversible adhesive contacts, the release into the circulation and the extravasation of tumour cells. CD44 is a family of glycoproteins involved in cell-cell and cell-matrix interactions. The v6 (variant exon v6) form of CD44 confers a metastatic potential onto some carcinoma cells. In the present study, the expression of CD44v6 on skin biopsies of 10 inflammatory skin diseases, 30 cutaneous lymphomas (CL), 11 reactive lymph nodes, 10 primary nodal non-Hodgkin's lymphomas (NHL) and 5 secondary nodal NHL was investigated immunohistochemically. None of the 10 nodal NHL were CD44v6 positive for the neoplastic B- or T-cells, whereas 11/12 CL with systemic spread showed a distinct CD44v6 expression in the skin. CD44v6 was not expressed on the tumour cells of skin biopsies of patients without systemic spread (18 cases of CL). In conclusion, CD44v6 expression is connected to an aggressive behaviour of CL.

Adult↗

PubMed2006

Activation of mammalian target of rapamycin signaling pathway contributes to tumor cell survival in anaplastic lymphoma kinase-positive anaplastic large cell lymphoma.

Anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) frequently carries the t(2;5)(p23;q35) resulting in aberrant expression of chimeric nucleophosmin-ALK. Previously, nucleophosmin-ALK has been shown to activate phosphatidylinositol 3-kinase (PI3K) and its downstream effector, the serine/threonine kinase AKT. In this study, we hypothesized that the mammalian target of rapamycin (mTOR) pathway, which functions downstream of AKT, mediates the oncogenic effects of activated PI3K/AKT in ALK+ ALCL. Here, we provide evidence that mTOR signaling phosphoproteins, including mTOR, eukaryotic initiation factor 4E-binding protein-1, p70S6K, and ribosomal protein S6, are highly phosphorylated in ALK+ ALCL cell lines and tumors. We also show that AKT activation contributes to mTOR phosphorylation, at least in part, as forced expression of constitutively active AKT by myristoylated AKT adenovirus results in increased phosphorylation of mTOR and its downstream effectors. Conversely, inhibition of AKT expression or activity results in decreased mTOR phosphorylation. In addition, pharmacologic inhibition of PI3K/AKT down-regulates the activation of the mTOR signaling pathway. We also show that inhibition of mTOR with rapamycin, as well as silencing mTOR gene product expression using mTOR-specific small interfering RNA, decreased phosphorylation of mTOR signaling proteins and induced cell cycle arrest and apoptosis in ALK+ ALCL cells. Cell cycle arrest was associated with modulation of G(1)-S-phase regulators, including the cyclin-dependent kinase inhibitors p21(waf1) and p27(kip1). Apoptosis following inhibition of mTOR expression or function was associated with down-regulation of antiapoptotic proteins, including c-FLIP, MCL-1, and BCL-2. These findings suggest that the mTOR pathway contributes to nucleophosmin-ALK/PI3K/AKT-mediated tumorigenesis and that inhibition of mTOR represents a potential therapeutic strategy in ALK+ ALCL.

Anaplastic Lymphoma Kinase↗

PubMed2001

T-cell-rich B-cell lymphoma. Analysis of clinical features, response to treatment, survival and comparison with diffuse large B-cell lymphoma.

OBJECTIVES: Clinical features, response to treatment and survival of T-cell-rich B-cell lymphoma (TCRBCL) patients were compared to those of a similar group of patients with diffuse large B-cell lymphoma (DLBCL). METHODS: Between 1992 and 1999, 10 patients with a diagnosis of TCRBCL were treated in our department. Over the same 7-year period, a group of 65 patients with DLBCL were diagnosed in the same department. Both groups of patients were treated with the same anthracycline-based chemotherapy. RESULTS: A significantly higher percentage of patients with TCRBCL presented with B-symptoms, elevated LDH, bone marrow infiltration and disseminated extranodal involvement compared to patients with DLBCL. TCRBCL patients responded poorly to combination chemotherapy, since only 3 of them achieved complete remission (33%) compared to 48 (75%) patients with DLBCL. All patients with TCRBCL who achieved complete response relapsed within the first 2 years while 65% of patients with DLBCL survive disease free for a median follow-up period of 4 years. The median overall survival for DLBCL patients has not been reached yet, while it was 18 months for TCRBCL patients. CONCLUSIONS: Although the number of patients in our study is small, it seems that patients with TCRBCL present with advanced disease, respond poorly to chemotherapy and display a short disease-free and overall survival compared to patients with DLBCL.

Aged↗

PubMed1993

Low-grade lymphoma following intensive treatment of large-cell lymphoma.

Progression of a low-grade non-Hodgkin's lymphoma into a more aggressive histologic pattern is a well-described phenomenon. The converse phenomenon, often called downgrading, is much less frequent. We report 2 patients in whom relapse with an indolent lymphoma was noted after chemotherapy for higher-grade disease. Other previously reported cases are reviewed. The implications for appropriate management and pathogenesis are discussed.

Adult↗

PubMedDate not supplied

Anaplastic large cell lymphoma presenting as a pleural effusion and mimicking primary effusion lymphoma. A report of 2 cases.

BACKGROUND: Systemic anaplastic large cell lymphoma (ALCL) is predominantly a nodal disease, but extranodal involvement can occur during the disease course or as the primary presentation. We report two rare cases of ALCL presenting with a pleural effusion, mimicking primary effusion lymphoma (PEL). CASES: Two patients, a 47-year-old woman and an 81-year-old man, presented with a pleural effusion for investigation. The pleural fluid contained abundant, large, lymphoid cells with marked nuclear atypia. These neoplastic cells strongly expressed CD30 and EMA and showed a T-cell phenotype (CD3+CD45RO+ for case 1 and CD4+ for case 2). Case 1, in addition, showed ALK1 expression. The tumor cells in both cases were negative for human herpes virus type 8 (HHV8) and Epstein-Barr virus (EBV). ALCL shows overlapping cytologic features with PEL, but the T-cell phenotype, ALK1 expression in case 1, lack of association with HHV8 and EBV, HIV seronegativity and subsequent discovery of nodal disease in case 2 were all in favor of ALCL over PEL. CONCLUSION: In rare cases a pleural effusion is the presenting feature of ALCL, and distinction from PEL depends on correlation with clinical findings, detailed immunophenotyping and study of the status of HHV8 and EBV.

Aged↗

PubMed2005

Follicular colonization of nodal marginal-zone B-cell lymphoma resembling follicular lymphoma: report of 6 cases.

The formation of neoplastic B-cell follicles is accepted as a diagnostic criterion of follicular lymphoma. However, extranodal marginal-zone B-cell lymphomas (MZBLs) of mucosa-associated lymphoid tissue (MALT) type also sometimes contain numerous lymphoid follicles and may even have a predominantly follicular growth pattern. However, morphologic, immunohistochemical, and genotypic findings suggest that lymphoid follicles in extranodal MZBLs are neoplastic follicles formed as the result of colonization of previously reactive follicles by tumor cells (centrocyte-like cells). We present here 6 cases of nodal MZBL demonstrating a follicular growth pattern. Immunohistochemical study demonstrated that the tumor cells were CD10-, CD20+, CD79a+,CD138-, Bcl-2+, Bcl-6- and IRF4+. Residual nonneoplastic follicular center cells were CD10+, CD20+, CD79a+, Bcl-2-, and Bcl-6+. CD21/CD23 immunostain demonstrated a disrupted follicular dendritic cell pattern characteristic of follicular colonization in extranodal MZBL of MALT type. Taken in conjunction with the morphologic findings, nodal MZBL may also show a follicular growth pattern similar to extranodal MZBL of MALT type. The marginal-zone nature is most recognizable on immunohistochemistry, although the histologic appearance alone may cause some diagnostic problems. It is important for pathologists to consider this type of lesion in diagnostic practice.

Adult↗

PubMed2002

Transformation of follicular lymphoma to diffuse large cell lymphoma is associated with a heterogeneous set of DNA copy number and gene expression alterations.

Genomic aberrations in a series of paired biopsy samples from patients who presented initially with follicle center lymphoma (FCL) and subsequently transformed to diffuse large B-cell lymphoma (DLBCL) were measured by array comparative genomic hybridization (CGH). The consequences of these aberrations on gene expression were determined by comparison with expression analysis on these specimens using cDNA microarrays. A heterogeneous pattern of acquired genomic abnormalities was observed upon transformation, some of which were recurrent in small subsets of patients. Some of the genomic aberration acquired upon transformation, such as gain/amplification of 1q21-q24, 2p16 (REL/BCL11A gene loci), 3q27-q29 (including the BCL6 locus), 7q11.2-q22.1, 12pter-q12, 18q21 (including the BCL2 locus) and Xq, and deletion of 6q22-q24, 13q14-q21 and 17p13 (P53 locus) have been previously implicated in the FCL/DLBCL pathogenesis. In addition, novel genomic imbalances not previously reported in association with FCL transformation, such as overrepresentation of 4p12-pter, 5p12-p15, 6p12.3-p21, 9p23, 9q13-q31, 16q, 17q21, and loss of 1p36.3, 4q21-q23, 5q21-q23, 9q31-qter, 11q24-q25, and 15q23, were identified. We observed a differential expression profile of many genes within regions of gain and deletion upon transformation, including novel target genes associated with FCL transformation. However, other genes did not show deregulated expression despite their location within these areas. In summary, the combination of array CGH and expression analysis provides a more comprehensive picture of the transformation of FCL to DLBCL. This process is associated with the acquisition of a variable spectrum of genomic imbalances affecting recurrent chromosomal areas that harbor overexpressed or underexpressed genes targeted upon transformation.

Allelic Imbalance↗

PubMed1995

CD30 (Ki-1)-positive anaplastic large-cell lymphomas in 13 patients with and 27 patients without human immunodeficiency virus infection: the first comparative clinicopathologic study from a single institution that also includes 80 patients with other human immunodeficiency virus-related systemic lymphomas.

PURPOSE: CD30 (Ki-1)-positive anaplastic large-cell lymphoma (Ki-1 ALCL) rarely has been described in patients with human immunodeficiency virus (HIV) infection. The purpose of this study was to characterize further the clinicopathologic features of Ki-1 ALCL in patients with HIV infection and, for the first time, to make a comparison with Ki-1 ALCL in patients without HIV infection. PATIENTS AND METHODS: From September 1987 to April 1993, 93 patients with HIV infection and systemic non-Hodgkin's lymphoma (NHL) were treated at the Cancer Center of Aviano, Italy; in 13 (14%), the diagnosis was of Ki-1 ALCL subtype. This group of patients was compared with the remaining 80 patients who had other HIV-related NHL and with another group of 27 patients with Ki-1 ALCL who were without a diagnosis of HIV infection. RESULTS: There was no case of a T-cell phenotype in the 13 HIV-positive Ki-1 ALCL patients, whereas there was such a phenotype in six of 27 (22%) HIV-negative Ki-1 ALCL patients. In regard to the general characteristics of the two groups with Ki-1 ALCL, more patients with stage IV, two or more extranodal sites at presentation, treatment-related leukopenia, and opportunistic infections as the cause of death were observed in the HIV-positive Ki-1 ALCL group. When these variables were compared with those of the other HIV-related NHL group, such differences were not present. CONCLUSION: Ki-1 ALCL is not a rare clinicopathologic entity among NHL in patients with HIV infection. The differences observed within the two Ki-1 ALCL groups of patients may be because of factors related to the HIV infection alone.

Adult↗

PubMed1997

Follicular large-cell lymphoma treated with intensive chemotherapy: an analysis of 89 cases included in the LNH87 trial and comparison with the outcome of diffuse large B-cell lymphoma. Groupe d'Etude des Lymphomes de l'Adulte.

PURPOSE: The aims of this study were as follows: (1) to analyze clinical, histopathologic characteristics, treatment outcome, and prognostic factors of patients with follicular large-cell lymphoma (FLCL); and (2) to compare them with those of patients with diffuse large B-cell lymphoma (DLCL) treated in the same therapeutic trial. PATIENTS AND METHODS: Eighty-nine FLCL patients who were histologically reviewed and who received an intensive chemotherapy regimen according to the LNH 87 protocol were analyzed and compared with 1,096 B-cell DLCL patients included in the same protocol. RESULTS: After intensive induction treatment, 59 patients (67%) achieved a complete remission [CR]. Estimated 5-year survival was 59%, and estimated 5-year freedom from progression (FFP) was 39%. Prognostic factors associated with shorter FFP were age greater than 60 years (P = .02), advanced clinical stage (P = .01), abnormal lactic dehydrogenase (LDH) level (P = .02), abnormal beta-2 microglobulin (P = .02), B symptoms (P = .03), bone marrow involvement (P = .04), and high expression of bcl-2 protein (P = .05). When compared with B-cell DLCL patients, FLCL patients were younger (P = .02), had a better Eastern Cooperative Oncology Group (ECOG) status (P = .05), less bulky mass (P = .04), more advanced clinical stages (P < .001), and more bone marrow involvement (P = .02). No significant difference was observed between FLCL and DLCL patients for response to therapy (67% v 67% of CR), 5-year overall survival (58% v 51%), 5-year disease-free survival (53% v 57%), or FFP survival (39% v 43%). CONCLUSION: FLCL patients have a favorable response rate and survival when treated with intensive chemotherapy. Their outcome is similar to that of B-cell DLCL patients, and a long-term FFP is observed for a substantial number of patients. Some adverse prognostic factors (including those of the International Prognostic Index, bone marrow involvement, and beta-2 microglobulin) have been identified to define a subset of patients who require other therapeutic approach.

Adolescent↗

PubMed1999

Primary mediastinal large B-cell lymphoma: a clinicopathologic study of 43 patients from the Nebraska Lymphoma Study Group.

PURPOSE: To investigate whether primary mediastinal large B-cell lymphoma (PMLBL) is a distinct clinicopathologic entity with a more aggressive course than other diffuse large B-cell lymphomas (DLBL). MATERIALS AND METHODS: All patients with CD20-positive DLBL who presented with a mediastinal mass measuring at least 5.0 cm and were treated with curative intent were identified. A control group of 352 patients with nonmediastinal DLBL was selected for comparison. RESULTS: The 43 patients with PMLBL had a male to female ratio of 20:23 and a median age of 42 years. Stage I/II disease was present in 58% of the patients, with only 9% having bone marrow involvement. A complete remission was achieved in 63% of the patients, and the 5-year overall and failure-free survivals were 46% and 38%, respectively. Among the clinical variables, an elevated serum lactate dehydrogenase level, a low performance score, more than one extranodal site, and an intermediate or high International Prognostic Index score were predictive of poor survival. When compared with the DLBL group, a younger median age was the only clinical feature that was significantly different in the PMLBL group. CONCLUSION: The clinical features of PMLBL do not appear to be significantly different from those of nonmediastinal DLBL. Although the younger age of onset, slight female predominance, mediastinal location, and size of the mass may justify the recognition of PMLBL as a clinical syndrome, additional evidence is needed to define it as a distinct disease entity.

Adolescent↗

PubMed2005

Large cleaved and immunoblastic lymphoma may represent two distinct clinicopathologic entities within the group of diffuse large B-cell lymphomas.

PURPOSE: The reliability of immunohistochemistry for subdividing diffuse large B-cell lymphomas (DLBCL) into germinal center B-cell-like (GCB) and non-GCB prognostic subgroups is debated. In this study we evaluated the prognostic significance of such subgrouping on a series of 153 DLBCL patients. Furthermore, we investigated whether both subgroups could comprise clinicopathologic entities recognized by their morphology and characterized by a distinct phenotype, specific genetic abnormalities, and clinical characteristics. PATIENTS AND METHODS: All samples from patients were reviewed and morphologically subdivided into large cleaved, immunoblastic, and not otherwise specified DLBCL. GCB and non-GCB immunohistochemical profiles were established. The presence of chromosomal translocations involving BCL2, BCL6, and MYC and/or rearrangements of these genes was investigated. RESULTS: Subdividing DLBCL with either a GCB or non-GCB immunophenotypic profile was not of prognostic significance. Nevertheless, CD10 expression was a predictor of favorable outcome, whereas high bcl-2 expression and BCL6 rearrangement were adverse predictors of disease-free survival. Interestingly, large cleaved DLBCL was clearly associated with a GCB immunophenotypic profile, CD10 expression, BCL2 rearrangement, age younger than 60 years, and low to low/intermediate International Prognostic Index risk, but was not of prognostic significance. In contrast, immunoblastic morphology was associated with a non-GCB profile and was a significant predictor of unfavorable DFS. CONCLUSION: Subdividing DLBCL into subgroups based on their immunohistochemical profile was not of prognostic significance. Nevertheless, it allowed the additional characterization of two lymphoma subgroups previously recognized in the Working Formulation. Both correspond to two distinct clinicopathologic entities within the DLBCL.

Adult↗

PubMed2005

CD5+ diffuse large B-cell lymphoma with c-myc/IgH rearrangement presenting as primary effusion lymphoma.

We report an instructive case of diffuse large B-cell lymphoma presenting as acute heart failure. A 69-year-old human immunodeficiency virus-negative man was admitted to our hospital for general fatigue. A computed tomographic scan of the chest and abdomen showed pericardial effusion, but there was no evidence of tumor masses, lymph node enlargement, or hepatosplenomegaly. During the chemotherapy, increased lactate dehydrogenase and pleural effusion appeared. The tumor cells in the effusion showed positivity for CD5, CD19, CD20, kappa chain, and Bcl-2 and negativity for CD10 and CD23. The chromosomes showed t(8;14)(q24;q32) with c-myc/immunoglobulin (Ig)H rearrangement, and the MIB-1 index was not high (60%). Neither human herpes virus 8 nor Epstein-Barr virus DNA was detected in the cells by polymerase chain reaction. The response to chemotherapy was very poor, and the patient died 4 months after the diagnosis. A spectrum of the symptoms of CD5+ lymphoma encompasses pericardial effusion and also can accompany c-myc/IgH rearrangement.

Aged↗

PubMed2001

High-dose therapy in lymphomas: a review of the current status of allogeneic and autologous stem cell transplantation in Hodgkin's disease and non-Hodgkin's lymphoma.

Autologous stem cell transplantation has proven to be beneficial in selected patients with Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL). In patients with HD, transplantation appears to increase event-free survival in patients who fail to enter complete remission with initial therapy. When a patient relapses after a complete remission, transplantation is probably the best option and particularly so if the remission lasted less than 1 year. Transplantation as part of primary therapy for very high-risk patients may be beneficial, but is not standard therapy at this time. For patients with diffuse large-cell NHL, transplantation can be considered standard therapy for relapsed patients if they have chemotherapy-sensitive disease. The use of transplantation for high-risk patients in complete remission is promising, but definite recommendations cannot be made at this time. For follicular lymphomas, selected patients seem to benefit and studies are ongoing. Finally, the use of allogeneic stem cell transplantation can be useful in a select group of younger patients.

Dose-Response Relationship, Drug↗

PubMed1998

p53 gene mutation in the bone-marrow of a patient with diffuse mixed cell type lymphoma at diagnosis predicting eventual progression to large cell lymphoma.

Mutations of the p53 tumor suppressor gene have been used as molecular genetic markers of disease and serve as a prognostic indicator in various malignancies including non-Hodgkin's lymphoma (NHL). Alterations in the p53 gene were investigated in a bone marrow sample from a NHL patient admitted for autologous bone marrow transplantation. Diffuse mixed small and large cell NHL, was initially diagnosed which eventually progressed to large cell lymphoma at relapse following poly-chemotherapy. A sequential technique of polymerase chain reaction-mediated single-strand conformational polymorphism (PCR-SSCP) of the p53 gene revealed a shift in one band of exon 6 in the bone marrow, collected at the time of initial diagnosis. No mutations were detected in exons 5, 7, 8 and 9. Direct sequencing of exon 6 detected a single base change from G to C resulting in an amino acid substitution from glycine to histidine. Results of this study and data reviewed from other publications suggest that the missense p53 mutation seen in this patient at the time of diagnosis may perhaps have been used to predict the eventual outcome of the disease. This could, therefore, serve as an important genetic disease marker particularly in bone marrow or peripheral blood samples initially collected and cryopreserved for future possible autologous transplantation.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2002

Multilevel dysregulation of STAT3 activation in anaplastic lymphoma kinase-positive T/null-cell lymphoma.

Accumulating evidence indicates that expression of anaplastic lymphoma kinase (ALK), typically due to t(2;5) translocation, defines a distinct type of T/null-cell lymphoma (TCL). The resulting nucleophosmin (NPM) /ALK chimeric kinase is constitutively active and oncogenic. Downstream effector molecules triggered by NPM/ALK remain, however, largely unidentified. Here we report that NPM/ALK induces continuous activation of STAT3. STAT3 displayed tyrosine phosphorylation and DNA binding in all (four of four) ALK+ TCL cell lines tested. The activation of STAT3 was selective because none of the other known STATs was consistently tyrosine phosphorylated in these cell lines. In addition, malignant cells in tissue sections from all (10 of 10) ALK+ TCL patients expressed tyrosine-phosphorylated STAT3. Transfection of BaF3 cells with NPM/ALK resulted in tyrosine phosphorylation of STAT3. Furthermore, STAT3 was constitutively associated with NPM/ALK in the ALK+ TCL cell lines. Additional studies into the mechanisms of STAT3 activation revealed that the ALK+ TCL cells expressed a positive regulator of STAT3 activation, protein phosphatase 2A (PP2A), which was constitutively associated with STAT3. Treatment with the PP2A inhibitor calyculin A abrogated tyrosine phosphorylation of STAT3. Finally, ALK+ T cells failed to express a negative regulator of activated STAT3, protein inhibitor of activated STAT3. These data indicate that NPM/ALK activates STAT3 and that PP2A and lack of protein inhibitor of activated STAT3 may be important in maintaining STAT3 in the activated state in the ALK+ TCL cells. These results also suggest that activated STAT3, which is known to display oncogenic properties, as well as its regulatory molecules may represent attractive targets for novel therapies in ALK+ TCL.

Anaplastic Lymphoma Kinase↗

PubMed2000

Anaplastic lymphoma kinase expression as a marker of malignancy. Application to a case of anaplastic large cell lymphoma with huge granulomatous reaction.

Anaplastic large cell lymphoma (ALCL) shows a wide morphologic spectrum, including the occurrence of reactive components obscuring the neoplastic population. This makes its distinction from hyperimmune reaction difficult. The authors describe an ALCL in a girl wha had a tick bite 20 days prior to clinical presentation. She developed a huge epithelioid reaction (an unprecedented finding for this tumor). The diagnostic controversies were solved by applying the ALKc antibody against anaplastic large cell lymphoma kinase (ALK), in conjunction with reagents anti-nucleophosmin (NPM), which showed the typical staining pattern observed in ALCL carrying t(2;5). Comprised within the epithelioid component there were large anaplastic cells and small-medium sized atypical elements displaying strong nuclear and cytoplasmic positivity for ALK and NPM (N-terminal region). This pattern, never observed in normal lymphocytes, corresponds to the presence of the product of the hybrid gene NPM/ALK produced by t(2;5). Following the diagnosis, the patient - whose general conditions were critical - underwent aggressive chemotherapy, achieving complete remission.

Anaplastic Lymphoma Kinase↗

PubMed2002

Nucleophosmin-anaplastic lymphoma kinase (NPM-ALK), a novel Hsp90-client tyrosine kinase: down-regulation of NPM-ALK expression and tyrosine phosphorylation in ALK(+) CD30(+) lymphoma cells by the Hsp90 antagonist 17-allylamino,17-demethoxygeldanamycin.

Anaplastic large cell lymphomas (ALCL) are characterized by the expression of a chimeric protein, NPM-ALK, which originates from fusion of the nucleophosmin (NPM) and the membrane receptor anaplastic lymphoma kinase (ALK) genes. The NPM-ALK kinase, on dimerization, shows phosphotransferase activity and, through its interaction with various ALK-adapter proteins, induces cell transformation and increases cell proliferation in vitro. The chaperones heat shock proteins 90 (Hsp90) and 70 (Hsp70) play a critical role in the folding and maturation of several oncogenic protein kinases, and perturbation of Hsp90 structure affects the stability and degradation of Hsp90- and Hsp70-bound substrates. This process is triggered by benzoquinone ansamycin antibiotics, Hsp90-binding small molecules. We have studied the effect of 17-allylamino,17-demethoxygeldanamycin (17-AAG), a benzoquinone ansamycin, on NPM-ALK steady-state level in ALCL cells. Treatment with 17-AAG decreased NPM-ALK expression and phosphorylation, thus impairing its association with phospholipase C-gamma, Src homology 2 domain-containing protein (Shc), growth factor receptor-bound protein 2 (Grb2), and insulin receptor substrate-1 (IRS-1). We also observed that NPM-ALK associates with Hsp90, and incubation with 17-AAG disrupts this complex without affecting Hsp90 expression. As shown previously for other Hsp90 client proteins, destabilization of the Hsp90/NPM-ALK complex induced by 17-AAG resulted in increased binding of the chimeric protein to Hsp70, which is known to affect protein degradation. Hsp/NPM-ALK complex formation appears to be independent of NPM sequences, because we were unable to coimmunoprecipitate NPM with either Hsp90 or Hsp70. Similar to NPM-ALK, the exogenously expressed variant fusion protein TPR-ALK showed decreased expression and phosphorylation after 17-AAG treatment, suggesting that the effect of 17-AAG on ALK chimeric proteins depends on the ALK portion and not on the partner protein moiety. Our data demonstrate that NPM-ALK cell content is determined by its interaction with Hsp90 and Hsp70, and suggest that the alteration of such associations can interfere with NPM-ALK function in ALCL cells.

Anaplastic Lymphoma Kinase↗