Biomedical subjects

K Pulford

Publications and source records attributed to K Pulford.

At least 37 records · Page 2Linked to original sources

PubMed2000

ALK expression in extranodal anaplastic large cell lymphoma favours systemic disease with (primary) nodal involvement and a good prognosis and occurs before dissemination.

AIMS: In anaplastic large cell lymphoma (ALCL), the site of origin has been described as an important prognostic factor. Recently, a fusion protein containing anaplastic lymphoma kinase (ALK) was described in systemic nodal ALCL, and shown to be associated with a good prognosis. The aims of this study were to investigate whether the presence of ALK protein differs between ALCL of different sites of origin; to determine whether ALK expression occurs before dissemination to other sites; and, finally, to investigate whether the site of origin remains a prognostic parameter in ALK negative ALCL. METHODS: ALK expression, as detected by immunohistochemistry using the monoclonal antibodies ALK1 and ALKc, was studied in 85 ALCLs from different sites of origin. In 22 patients, ALK expression was studied in multiple biopsies from different sites (including 13 skin, 16 lymph node, and nine other). Overall survival time was analysed using the Kaplan Meier method. RESULTS: ALK expression was found in 20 of 51 systemic ALCLs with (primary) nodal involvement. No ALK expression was found in 15 primary cutaneous, 14 gastrointestinal, and five nasal ALCLs. Multiple and subsequent biopsies of patients showed ALK expression to be identical to that seen in the primary diagnostic biopsy. Kaplan Meier survival curves showed that in ALK negative ALCLs originating from different sites, primary cutaneous cases are associated with an excellent overall survival, whereas the other cases show a comparable five years survival of less than 40%. CONCLUSIONS: If present, ALK expression favours systemic ALCL with (primary) nodal involvement, and can be used in differentiating between extranodal involvement of systemic (nodal) ALCL and primary extranodal ALCL. ALK is expressed consistently in multiple biopsies of a given patient, indicating that the chromosomal abnormality leading to aberrant ALK expression occurs before dissemination to other sites. Finally, in ALK negative non-cutaneous ALCLs, different sites of origin show comparable poor survival.

Adolescent↗

PubMed1999

Lymphomas expressing ALK fusion protein(s) other than NPM-ALK.

The tumor cells in ALK-positive lymphoma ("ALKoma") usually express the product of the NPM-ALK chimeric gene, generated by the t(2;5) chromosomal translocation. However, 10% to 20% of ALK-positive lymphomas express ALK fusion protein(s) other than NPM-ALK, and in this report, we describe the immunohistologic and clinicopathologic features of 15 such cases. The absence of the NPM-ALK fusion gene was confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR) in 8 cases and by fluorescence in situ hybridization (FISH) analysis in a further 2 cases. In each case, ALK staining was restricted to the cytoplasm and the N-terminus of NPM to the nucleus (contrasting with lymphomas expressing NPM-ALK in which cytoplasmic as well as nuclear labeling is seen). However, in the course of screening 53 ALK-positive lymphomas, 2 biopsies were found that had a "cytoplasm-only" ALK staining pattern but that nevertheless were shown to carry the (2;5) (by NPM staining and RT-PCR). The 15 cases resembled typical NPM-ALK-positive lymphomas in that all were of T or null phenotype, usually occurred in young male patients, and frequently presented with advanced disease associated with systemic symptoms and extranodal involvement. Moreover, their prognosis was excellent and indistinguishable from that of classical t(2;5)-positive tumors, but was clearly different from that of ALK-negative anaplastic large-cell lymphomas. These results suggest that lymphomas carrying variants of the NPM-ALK fusion protein can be detected by immunostaining for ALK and NPM and also that they can be grouped with classical t(2;5)-positive tumors as a single entity (ALK-positive lymphoma or "ALKoma") that shows a better prognosis than ALK-negative anaplastic large-cell lymphoma.

Adolescent↗

PubMed1999

TRK-fused gene (TFG) is a new partner of ALK in anaplastic large cell lymphoma producing two structurally different TFG-ALK translocations.

Anaplastic large cell lymphoma (ALCL) is associated with the t(2;5)(p23;q35), which generates the NPM-ALK fusion gene encoding an 80-kD protein. Several studies have suggested that genes other than NPM may be fused to the ALK gene. Here we have identified TRK-fused gene (TFG) as a new ALK partner in 2 ALCL, 1 of which exhibited a t(2;3)(p23;q21). In these cases, TFG was involved in 2 different fusion genes, TFG-ALK(S) and TFG-ALK(L), coding respectively 85-kD and 97-kD chimeric proteins. The ALK breakpoint in these translocations was the same as in the classic t(2;5) translocation. These 2 proteins were both active in an in vitro tyrosine kinase assay showing that the new cloned cDNA sequences are translated into chimeric proteins with functional activity. These findings indicate that TFG can provide an alternative to NPM as a fusion partner responsible for activation of the ALK and the pathogenesis of ALCL.

Adult↗

PubMed1999

t(1;2)(q21;p23) and t(2;3)(p23;q21): two novel variant translocations of the t(2;5)(p23;q35) in anaplastic large cell lymphoma.

Cytogenetic investigations in two cases of anaplastic large cell lymphoma (ALCL) showed novel variants of the classical (2;5)(p23;q35) translocation, namely a t(1;2)(q21;p23) and a t(2;3)(p23;q21). The tumor cells in both cases gave positive immunohistochemical labeling for ALK protein (with both monoclonal and polyclonal antibodies), demonstrating that these translocations induce aberrant expression of this kinase and suggesting that genes other than NPM can activate the ALK gene in ALCL. These two cases were shown by an in vitro kinase assay to express ALK kinases (104 kD and 97 kD, respectively), which differed in size from the classical NPM-ALK fusion product (80 kD). Moreover, ALK expression was confined to the cytoplasm of the tumor cells in each case, supporting the hypothesis that the observed nuclear localization of NPM-ALK in classical ALCL is not the site of oncogenic activity of the ALK kinase.

Adolescent↗

PubMed1999

The T-cell activation markers CD30 and OX40/CD134 are expressed in nonoverlapping subsets of peripheral T-cell lymphoma.

The tumor necrosis factor (TNF) receptor family includes several important markers of activation in T cells. We examined expression patterns of two T-cell-associated members of these receptors, namely CD30 and OX40/CD134, in 148 cases of T-cell lymphoma to identify possible objective immunohistochemical criteria for subclassification of these tumors. CD30 expression was characteristic of tumors with an anaplastic (46/47 cases [98%]) or large-cell (10/21 [48%]) morphology and was seen in only scattered cells in other tumor types. In contrast, large numbers of OX40/CD134(+) tumors cells were typical of angioimmunoblastic lymphoma (15/16 [94%]), angiocentric lymphoma (4/4), a subset of large-cell lymphomas (10/21 [48%]), and lymphomas with a prominent histiocytic component (6/7 [86%]). Strong OX40/CD134 and CD30 coexpression was seen in only 4% of tumors, typically those with an anaplastic/Hodgkin's-like appearance. OX40/CD134 expression was characteristic of tumors composed of activated CD4(+) T cells and was not seen in small-cell T-cell lymphomas, lymphoblastic lymphomas, or other tumor types, including B-cell lymphomas or carcinomas. These results suggest that immunostaining for OX40/CD134 may be helpful in subclassification of peripheral T-cell lymphomas and that the patterns of TNF receptor family expression in these tumors may parallel those seen within nonneoplastic helper T-cell subsets.

Antigens, CD↗

PubMed1999

A new fusion gene TPM3-ALK in anaplastic large cell lymphoma created by a (1;2)(q25;p23) translocation.

Anaplastic large cell lymphomas (ALCL) are frequently associated with the t(2;5)(p23;q35). This translocation fuses the nucleophosmin (NPM) gene at 5q35, which encodes a nucleolar protein involved in shuttling ribonucleoproteins from the cytoplasm to the nucleus, to the anaplastic lymphoma kinase (ALK) gene at 2p23, encoding a tyrosine kinase receptor. In this report, we describe a typical case of ALCL whose malignant cells exhibited a novel (1;2)(q25;p23) translocation. These cells expressed ALK protein, but, in contrast to t(2;5)-positive ALCL (which show cytoplasmic, nuclear, and nucleolar staining), labeling was restricted to the malignant cell cytoplasm. Using a polymerase chain reaction (PCR)-based technique to walk on chromosome 2 from the known ALK gene across the breakpoint, we showed that the gene involved at 1q25 is TPM3, encoding a nonmuscular tropomyosin. We subsequently identified, using reverse transcription-PCR analysis of cases showing similar ALK cytoplasm-restricted staining, fusion of the ALK and TPM3 genes in 2 other cases of ALCL. The TPM3 gene has been previously found in papillary thyroid carcinomas as a fusion partner with the TRK kinase gene. We showed that TPM3 is constitutively expressed in lymphoid cell lines, suggesting that, in these t(1;2)-bearing ALCL cases, the TPM3 gene contributes an active promoter for ALK expression. Activation of the ALK catalytic domain probably results from homodimerization of the hybrid protein TPM3-ALK, through the TPM3 protein-protein interaction domain. The present cases of ALCL associated with a novel t(1;2)(q25;p23) demonstrate that at least one fusion partner other than NPM can activate the intracytoplasmic domain of the ALK kinase.

Anaplastic Lymphoma Kinase↗

PubMed1999

Adverse effects of activated cytotoxic T lymphocytes on the clinical outcome of nodal anaplastic large cell lymphoma.

Systemic (nodal) anaplastic large cell lymphoma (ALCL) is a subgroup of T-cell non-Hodgkin's lymphomas with a relatively favorable clinical outcome. Part of systemic ALCLs harbor a genetic aberration (usually the t(2;5)(p23;q35) translocation) containing the anaplastic lymphoma kinase (ALK) gene at 2p23, which results in aberrant expression of the ALK protein. Recently, we have shown that the presence of high percentages of activated cytotoxic T lymphocytes (CTLs) in tumor biopsy specimens of Hodgkin's disease (HD) is associated with a poor prognosis. In the present study, we investigated the prognostic value of percentages of activated CTLs in combination with ALK expression in primary nodal ALCL. Primary nodal biopsies of 42 patients with ALCL were investigated for the percentage of activated CTLs (quantified using Q-PRODIT) and the expression of ALK by immunohistochemistry using monoclonal antibodies (MoAbs) directed against T-cell antigen granzyme B (GrB) and ALK, respectively. These parameters were evaluated for their predictive value regarding progression-free and overall survival time. The presence of a high percentage of activated CTLs (ie, >/=15%) was found to be an unfavorable prognostic marker. In combination with a lack of ALK expression, it was possible to identify a group of patients with a very poor prognosis. In this group, 13 of 16 patients died within 2 years as a result of the disease. Of the remaining 26 patients, only three (all ALK negative) died (P <.0001). Furthermore, the percentage of activated CTLs combined with ALK status appeared to be of stronger prognostic value than the International Prognostic Index (IPI). We conclude that a high percentage of activated CTLs present in biopsy material of patients with primary nodal ALCL is a strong indicator for an unfavorable clinical outcome. The combination of ALK expression and percentage of activated CTLs appears to be more sensitive than the IPI in identifying a group of patients with a highly unfavorable clinical outcome who may be eligible for alternative (high dose) therapy schemes.

Anaplastic Lymphoma Kinase↗

PubMed1999

Immunohistochemical screening for oncogenic tyrosine kinase activation.

Tyrosine kinases causing the abnormal phosphorylation of intracellular proteins have been shown to contribute to oncogenic transformation in a number of human neoplasms. Immunohistological staining of routine biopsy sections for increased levels of phosphotyrosine may therefore provide a simple means of screening for tumours containing activated tyrosine kinases. In this study, monoclonal antibodies to phosphotyrosine were used to immunostain a cell line and tumour biopsies from lymphomas known to contain the activated anaplastic-lymphoma-kinase (ALK) tyrosine kinase. A range of normal and other neoplastic tissues were also immunostained for comparison. An anaplastic large cell lymphoma (ALCL) cell line carrying the (2;5) translocation, which creates the activated nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) tyrosine kinase, was strongly labelled. Routine tissue biopsies from five cases of ALK-positive ALCL were also strongly positive for phosphotyrosine. The characteristic granular cytoplasmic labelling pattern for phosphotyrosine observed in a B-cell lymphoma (expressing full length ALK kinase) was identical to that obtained using an ALK-specific antibody, thus confirming that labelling for phosphotyrosine in lymphoma cells reflects the presence of an activated kinase. When normal lymphoid tissues were stained, there was little or no labelling for phosphotyrosine, but stronger labelling was seen in other cells and tissues; for example, endothelial cells and some carcinoma samples. Whilst the strong labelling for phosphotyrosine observed in the lymphoma cells is due to the presence of activated ALK, the strong staining of some normal cells presumably represents physiologically active kinases and this should be taken into account when interpreting the immunostaining of non-lymphoid tumours. The simplicity of this method, however, means that it offers a new rapid approach to the screening of large numbers of tumours for the presence of aberrant tyrosine kinase activation, particularly if they arise from tissues which normally contain only background levels of phosphotyrosine.

Antibodies, Monoclonal↗

PubMed1999

Identification of the CD85 antigen as ILT2, an inhibitory MHC class I receptor of the immunoglobulin superfamily.

The CD85 molecule was originally defined at the Fifth Workshop on Leucocyte Antigens in 1993 by two monoclonal antibodies, VMP55 and GHI/75. This cell-surface glycoprotein is expressed on B cells, monocytes, and subpopulations of T and natural killer (NK) cells, and particularly high levels are expressed by normal and neoplastic plasma cells and by hairy cell leukemia B cells. We affinity purified the CD85 antigen and obtained tryptic peptide sequence which indicated that this molecule might be ILT2, a recently described inhibitory major histocompatibility complex class I receptor of the immunoglobulin superfamily. This was confirmed by showing that both of the original anti-CD85 mAbs stained ILT2 transfectants. The cell signaling role demonstrated for ILT2 is consistent with the previously reported involvement of CD85 in T cell activation.

Antibodies, Monoclonal↗

PubMed1999

Biochemical detection of novel anaplastic lymphoma kinase proteins in tissue sections of anaplastic large cell lymphoma.

The (2;5) translocation, found in many T-cell and null cell anaplastic large cell lymphomas (ALCLs), creates a hybrid gene encoding the 80-kd NPM-ALK protein. Typically neoplastic cells show labeling of both nucleus and cytoplasm for anaplastic lymphoma kinase (ALK) and for the N-terminus of nucleophosmin (NPM). However, 10-20% of cases exhibit cytoplasmic labeling only for ALK, indicating the probable presence of variants of the classical (2;5) translocation that do not involve the NPM gene. We report the detection (using Western blotting and an in vitro kinase assay) in seven such ALCL cases, of ALK proteins with molecular masses of 85 kd, 97 kd (one case exhibiting a (2;3)(p23;q21) translocation), 104 kd (one case carried a (1;2)(q21;p23) translocation), and 113 kd. Tyrosine kinase activity was detected in four of these proteins, but the N-terminal portion of NPM could not be detected. These results show how ALCL cases that express ALK proteins other than NPM-ALK can be detected by sensitive biochemical techniques using routine cryostat sections.

Animals↗

PubMed1999

Lymphocyte-specific protein 1: a specific marker of human leucocytes.

While both murine and human homologues of the LSP1 gene (lymphocyte-specific gene 1) and its protein products have been identified, studies on human LSP1 have been limited. The present report describes a detailed immunocytochemical study of the distribution and localization of human LSP1 in both normal and neoplastic cells and tissues. The specificity of the monoclonal anti-LSP1 reagent was confirmed by expression cloning and transfection studies. The intracellular 60 000 MW LSP1 protein was found to be present in peripheral blood B cells, monocytes and granulocytes but absent in a subpopulation of circulating T cells (10-15% of CD3-positive T cells). The presence of LSP1 protein in medullary thymocytes, but only in scattered cortical thymocytes, provided additional evidence for heterogeneity of expression in T cells. Novel observations also included the presence of LSP1 in plasma cells, dendritic cells and Langerhans' cells. The leucocyte-restricted distribution of LSP1 protein means that it may play an important role in haematopathology. LSP1 protein was detected in a wide range of leukaemias and lymphomas, particularly of B-cell origin, and in tumour cells in classical Hodgkin's disease. Of interest was the indication of a reciprocal relationship in the expression of LSP1 and ALK (anaplastic lymphoma kinase) proteins in patients with anaplastic large cell lymphoma. As the anti-LSP1 reagent used in the present study recognizes a formalin-resistant epitope it should be of considerable value in the diagnosis of routinely fixed material.

Anaplastic Lymphoma Kinase↗

PubMed1999

A cytotoxic phenotype does not predict clinical outcome in anaplastic large cell lymphomas.

AIM: To investigate whether anaplastic large cell lymphomas (ALCL) expressing cytotoxic proteins have a relatively worse clinical outcome compared with ALCL lacking a cytotoxic phenotype. METHODS: 59 primary cases of ALCL originating from different sites were investigated by immunohistochemistry for the presence of the cytotoxic proteins T cell intracytoplasmic antigen (TIA-1) and granzyme B in the neoplastic cells. Since site of origin and expression of anaplastic lymphoma kinase (ALK) strongly influence prognosis, the presence of a cytotoxic phenotype was also investigated in relation to the primary site of origin (lymph node, gut, or skin) and ALK expression. The prognostic value was investigated by analysis of overall and relapse-free survival time, including Cox regression analysis. RESULTS: 39 of 59 ALCL (66%) appeared to have a cytotoxic phenotype as shown by expression of TIA-1 or granzyme B or both in the neoplastic cells. The presence of a cytotoxic phenotype did not have any influence on prognosis. Even when the survival data were corrected for site of origin and stage at presentation or were analysed separately for ALK positive and negative cases, no prognostic influence of a cytotoxic phenotype was observed. CONCLUSIONS: In primary biopsies of patients with ALCL, the presence of a cytotoxic phenotype is not related to clinical outcome of the disease.

Adult↗

PubMed1998

Characterization of t(2;5) reciprocal transcripts and genomic breakpoints in CD30+ cutaneous lymphoproliferations.

NPM-ALK chimeric transcripts, encoded by the t(2;5), lead to an aberrant expression of ALK by CD30+ systemic lymphomas. To determine if t(2;5) is involved in cutaneous lymphoproliferative disorders, we studied 37 CD30+ cutaneous lymphoproliferations, 27 mycosis fungoides (MF), and 16 benign inflammatory disorders (BID). NPM-ALK transcripts were detected by nested reverse transcription-polymerase chain reaction (RT-PCR) in 1 of 11 lymphomatoid papulosis (LyP), 7 of 15 CD30+ primary cutaneous T-cell lymphoma (CTCL), 3 of 11 CD30+ secondary cutaneous lymphoma, 6 of 27 MF, and 1 of 16 BID. However, the expression of NPM-ALK transcripts was not associated with ALK1 immunoreactivity in MF, LyP, or BID cases. Only 1 CD30+ primary CTCL and 3 CD30+ secondary cutaneous lymphoma were ALK1 immunoreactive. The ALK1+ cases were also characterized by amplification of tumor-specific genomic breakpoints on derivative chromosome 5. These cases, except for 1 secondary cutaneous lymphoma, were also characterized by reciprocal breakpoints on derivative chromosome 2, leading to the expression of reciprocal ALK-NPM transcripts. Amplification of chromosomal breakpoints on both derivative chromosomes could represent an alternative to conventional cytogenetics for the diagnosis of t(2;5) and seems to be more reliable than the detection of cryptic NPM-ALK transcripts by nested RT-PCR.

Base Sequence↗

PubMed1998

ALK-positive lymphoma: a single disease with a broad spectrum of morphology.

The t(2;5)(p23;q35) translocation, associated with anaplastic large-cell lymphoma (ALCL), results in the expression of a chimeric NPM-ALK protein that can be detected by the ALK1 monoclonal antibody. This report describes the morphologic and phenotypic spectrum of 123 cases of lymphoma that all express ALK protein. The results provide strong evidence that the morphologic patterns of ALCL described in previous reports as representing possible subtypes of ALCL, eg, common type, lymphohistiocytic, or small cell patterns, are morphologic variants of the same disease entity. All of these morphologic patterns could be found within this series, and in some patients different subtypes coexisted in a single biopsy or were found in successive biopsies from a single patient. The link between these morphologic subtypes is further reinforced by the presence in all cases of a highly characteristic large cell, with an eccentric nucleus and an eosinophilic paranuclear region. We suggest that this cell can be considered as a major distinguishing feature of ALK-positive lymphomas. Another characteristic of these tumors was the perivascular pattern of neoplastic cell infiltration seen in a significant number of cases. In addition to ALK protein, all tumors expressed epithelial membrane antigen and lacked CD15, features that may be of value in differentiating ALCL from Hodgkin's disease. In the majority of cases (84%), malignant cells showed both a cytoplasmic and nuclear staining for ALK1 and thus presumably carried the 2;5 translocation, but staining was restricted to the cytoplasm in a few cases, suggesting that translocations other than t(2;5) may induce expression of ALK protein. We conclude from this study that ALK-positive neoplasms represent a distinct entity. Because their morphology is often neither anaplastic nor large cell, we suggest that they should henceforward be referred to as ALK lymphomas.

Adolescent↗

PubMed1998

Co-expression of CD79a (JCB117) and CD3 by lymphoblastic lymphoma.

Acute lymphoblastic leukaemia/lymphoma is a malignant disorder derived from the clonal proliferation of lymphoid precursor cells. Whether the tumour cells are of B- or T-cell type is an important criterion for prognosis which has not been available previously to pathologists, due to the lack of a reliable early B-cell marker functioning on routinely processed material. This has changed with the production of monoclonal antibodies against the B-cell signalling molecule CD79a. CD79a is expressed on normal and neoplastic B cells from the early stages of B-cell maturation and has been considered to be B-cell-specific. Currently available antibodies against CD79a, in particular JCB117, allow the identification of B cells, and hence B lymphoblastic disease, in paraffin-embedded material. In this study, the expression of CD79a (JCB117) and CD3 has been investigated in 149 cases of T and 68 cases of B lymphoblastic leukaemia/lymphoma. For the first time, co-expression of CD79a (JCB117) and CD3 is reported in 10 per cent of cases of T lymphoblastic leukaemia/lymphoma. This finding raises questions about the co-expression of T- and B-cell markers in the development of lymphocytes, benign as well as malignant, and alerts pathologists to a potential problem in diagnosis.

Antigens, CD↗

PubMed1998

ALK expression defines a distinct group of T/null lymphomas ("ALK lymphomas") with a wide morphological spectrum.

The t(2;5)(p23;q35) translocation associated with CD30-positive anaplastic large cell lymphoma results in the production of a NPM-ALK chimeric protein, consisting of the N-terminal portion of the NPM protein joined to the entire cytoplasmic domain of the neural receptor tyrosine kinase ALK. The ALK gene products were identified in paraffm sections by using a new anti-ALK (cytoplasmic portion) monoclonal antibody (ALKc) that tends to react more strongly than a previously described ALK1 antibody with the nuclei of ALK-expressing tumor cells after microwave heating in 1 mmol/L ethylenediaminetetraacetic acid buffer, pH 8.0. The ALKc monoclonal antibody reacted selectively with 60% of anaplastic large cell lymphoma cases (60 of 100), which occurred mainly in the first three decades of life and consistently displayed a T/null phenotype. This group of ALK-positive tumors showed a wide morphological spectrum including cases with features of anaplastic large cell lymphoma "common" type (75%), "lymphohistiocytic" (10%), "small cell" (8.3%), "giant cell" (3.3%), and "Hodgkin's like" (3.3%). CD30-positive large anaplastic cells expressing the ALK protein both in the cytoplasm and nucleus represented the dominant tumor population in the common, Hodgkin's-like and giant cell types, but they were present at a smaller percentage (often with a perivascular distribution) also in cases with lymphohistiocytic and small cell features. In this study, the ALKc antibody also allowed us to identify small neoplastic cells (usually CD30 negative) with nucleus-restricted ALK positivity that were, by definition, more evident in the small cell variant but were also found in cases with lymphohistiocytic, common, and "Hodgkin's-like" features. These findings, which have not been previously emphasized, strongly suggest that the neoplastic lesion (the NPM-ALK gene) must be present both in the large anaplastic and small tumor cells, and that ALK-positive lymphomas lie on a spectrum, their position being defined by the ratio of small to large neoplastic cells. Notably, about 15% of all ALK-positive lymphomas (usually of the common or giant cell variant) showed a cytoplasm-restricted ALK positivity, which suggests that the ALK gene may have fused with a partner(s) other than NPM. From a diagnostic point of view, detection of the ALK protein was useful in distinguishing anaplastic large cell lymphoma cases of lymphohistiocytic and small cell variants from reactive conditions and other peripheral T-cell lymphoma subtypes, as well as for detecting a small number of tumor cells in lymphohemopoietic tissues. In conclusion, ALK positivity appears to define a clinicopathological entity with a T/null phenotype ("ALK lymphomas"), but one that shows a wider spectrum of morphological patterns than has been appreciated in the past.

Anaplastic Lymphoma Kinase↗

PubMed1998

TAL1 expression does not occur in the majority of T-ALL blasts.

The TAL1 gene is disrupted by translocation or deletion (tal(d)) in up to 30% of T-cell acute lymphoblastic leukaemia (T-ALL), leading to aberrant transcriptional activation, as a SIL-TAL1 fused transcript in tal(d). It has been suggested that TAL1 transcription occurs in approximately 50% of a T-ALLs without apparent rearrangement. SIL-TAL1 was positive in 15/60 (25%) of T-ALL, whereas wild-type TAL1 transcripts were detected in all 13 SIL-TAL1 and in 19/43 (44%) T-ALL without SIL-TAL1. To investigate the cellular origin of TAL1 we exploited the fact that GATA1 and TAL1 are co-ordinately expressed in non-lymphoid haemopoietic cells, whereas only the latter is found in T-ALL. GATA1 was detected in 10/23 (43%) TAL1-negative T-ALLs but in 17/19 (89%) 'unexplained' TAL1-positive cases, suggesting a common non-lymphoid cellular origin. Immunocytochemical analysis with a TAL1-specific monoclonal antibody showed nuclear expression in the blasts of 10/34 (29%) cases, including 8/10 SIL-TAL1+ and two RT-PCR TAL1+, SIL-TAL1- cases. In the remaining cases TAL1 expression was restricted to a minor population (< 5%) of larger, strongly TAL1-positive cells which comprised erythroid cells, CD34+ CD3- precursors and an unidentified TAL1+ CD45- population which morphologically resembled monocytes/macrophages. We therefore suggest that appropriate diagnostic evaluation of T-ALL should include molecular detection of SIL-TAL1 transcripts and in situ immunocytochemical detection of TAL1 protein expression by leukaemic blasts. This approach will enable accurate analysis of the prognostic significance of TAL1 deregulation in T-ALL.

Adolescent↗

PubMed1998

Statistical evaluation of diagnostic and prognostic features of CD30+ cutaneous lymphoproliferative disorders: a clinicopathologic study of 65 cases.

Several clinical and histopathologic features of 65 CD30+ cutaneous lymphoproliferations were evaluated for their diagnostic value between CD30+ primary versus secondary cutaneous lymphomas and for their prognostic significance. Primary cutaneous disease, spontaneous regression, and absence of extracutaneous spreading (but not age < or =60 years) were associated with a better prognosis. Epithelial membrane antigen, BNH9, CD15 or CBF.78 antigen were expressed in all types of cutaneous lymphoproliferations. However, epithelial membrane antigen immunoreactivity was more frequently expressed in CD30+ secondary cutaneous large-cell lymphoma. Among CD30+ primary cutaneous large-cell lymphoma, CD15 expression was only seen in localized skin lesions. P53 expression was not associated with spontaneous regression, extracutaneous spreading, or survival. Nested reverse transcriptase-polymerase chain reaction allowed the detection of NPM-ALK transcripts in 10 of 26 CD30+ primary and in 3 of 11 secondary cutaneous large-cell lymphomas. The ALK protein was detected in only 1 of 50 primary and in 4 of 15 secondary cutaneous CD30+ lymphoproliferations. In CD30+ primary cutaneous lymphoproliferation, NPM-ALK transcripts might be expressed by very rare normal or tumoral cells that are undetectable by immunohistochemistry. However, the expression of either NPM-ALK transcripts or ALK-protein was not correlated with prognosis or age in CD30+ cutaneous lymphoproliferations.

Biomarkers, Tumor↗